# All Referential Sieve Conventions

This document is intended to be a community effort for documenting all conventions used when playing Referential Sieve. Conventions are divided into four categories:
- Basic Conventions are used in a player's first several games. These are intentionally minimal to focus on the core ideas of the system.
- Advanced and Expert Conventions are assumed to be enabled in expert games.
- Experimental Conventions are not assumed to be enabled unless stated before the game.

This document is editable to anybody with the link. Please feel free to improve the descriptions of existing conventions, add your own Experimental Conventions, or suggest changes to the documentation approach entirely! When adding/changing conventions, please also make a post in the [#conventions-dev forum](https://discord.com/channels/923261838836248646/1056076562425991178) on the [Hanabi Central](https://discord.gg/FJP42bjXf7) Discord server afterwards so people can be aware of it and potentially discuss the change.

For 3 or more player games, the Reactor family of conventions has supplanted Referential Sieve in power and popularity.
Descriptions of those can be found https://hanabi.wiki/conventions.

## Basic Conventions

This section contains the same conventions as [Intro to Referential Sieve](https://hackmd.io/@timotree3/Byn3cjSZK). One of the goals of that document is to be short and sweet, so the explanations here might have more redundancy for the sake of clarity.

### Summary

- Chop: Players are allowed to discard their leftmost card, called their chop, if they do not receive a clue.
- (We say that this card is "on chop" or "their chop")
- *Referential Play Clue*: We indicate that a card is playable by color-cluing the card to its right.
- (Also known as a *Play Clue* or *Color Push*)
- *Referential Discard Clue*: We indicate that a card is safe to discard by number-cluing the card to its left. The card is then on chop.
- (Also known as a *Save Clue*)
- Safe Action: A player has a safe action if they know they can play one of their cards, or they know they can safely discard one of their cards.
- *Sieve Principle*: When we care about the card on someone's chop, we save it by giving them a safe action. (And when we don't care about the card, we *don't* give them an action.)
- This way, useless cards are never allowed to move past slot #1. Slot #1 is acting as a *sieve*.
- *Fill-in Clue*: We indicate that an already clued card is playable or safe to discard by simply giving a clue that reveals it. Such a clue does not have any additional meaning, even if it touches new cards.
- *Good Touch Principle*: We assume that our clued cards are not trash.
- (A trash card is a duplicate copy of a card that has been played or *Play Clued*)
- *Playable Rank*: When all of the cards of a particular rank are playable or trash, a clue of that rank is not a *Referential Discard Clue*; it just means to play the touched cards.

### Chop

You're only allowed to discard your chop if you have no alternative safe actions. Every time you draw a new card, your chop is reset to leftmost, even if you have previously received a *Referential Discard Clue*.

### *Referential Play Clues*

When a *Referential Play Clue* touches multiple cards, how do I know what card to play? And how can I indicate that someone's rightmost card is playable?

- Each unclued card can be "referred to" by cluing the unclued card to its right.
- The rightmost unclued card can be referred to by cluing the leftmost unclued card.
- (This is known as *Wraparound*)
- Cards that have *already* been clued are completely ignored for *Referential Clues*. They cannot be referred to, and they cannot be clued to refer to another card.
- (Cards that are *newly* clued by the *Referential Play Clue* can still be referred to.)
- When a *Referential Play Clue* could be referring to multiple possible cards, it means to play the closest one to chop.

See [Focus and Target](#Focus-and-Target) for an alternative explanation of referential clues.

<details>
<summary><b>Examples (Click to show)</b></summary>

For example, if slot #1 is on chop, and slot #2 has already been clued,

- Slot #1 can be *referred to* by cluing slot #3.
- Slot #3 can be *referred to* by cluing slot #4.
- Slot #4 can be *referred to* by cluing slot #5.
- Slot #5 can be *referred to* by cluing slot #1.
- If a *Referential Play Clue* touches slots #2, #4, and #5,
- It could be *referring to* slot #3 or slot #4.
- Slot #3 is closer to chop than slot #4.
- So the clue means to play slot #3.
- If a *Referential Play Clue* touches slots #1 and #3,
- It could be *referring to* slot #5 or slot #1.
- Slot #1 is closer to chop than slot #5.
- So the clue means to play slot #1.
- (Sometimes a *Referential Play Clue* can mean to play a newly clued card!)
- If a *Referential Play Clue* touches slot #1,
- It can only be *referring to* slot #5.
- So the clue means to play slot #5.
</details>
<br/>

### *Referential Discard Clues*

When a *Referential Discard Clue* touches multiple cards, how do I know what card is on chop? And how can I tell someone not to discard anything at all?

- When a *Referential Discard Clue* touches multiple new cards, find the newly touched card which is closest to chop. The clue means to discard the currently unclued card to its right.
- Note: A *Referential Discard Clue* never means to discard a clued card. (Unlike a *Referential Play Clue*, which can sometimes refer to a newly clued card.)
- If there is no unclued card to the right, then the clue means not to discard **anything**.
- (This is known as a *Lock Clue*)

See [Focus and Target](#Focus-and-Target) for an alternative explanation of referential clues.

<details>
<summary><b>Examples (Click to show)</b></summary>

- If slot #1 is on chop, and a *Referential Discard Clue* touches slot #2 and slot #3,
- Since nothing was already clued, both slot #2 and slot #3 are both newly touched cards.
- Slot #2 is closer to chop.
- The unclued card to right of slot #2 is slot #4
- The clue means to discard slot #4.
- After that clue, if another *Referential Discard Clue* touches slot #1 and slot #4,
- Slot #4 is currently on chop (due to the previous *Referential Discard Clue*)
- There are two newly touched cards, slot #1 and slot #4.
- Slot #4 is closer to chop.
- The unclued card to right of slot #4 is slot #5
- The clue means to discard slot #5
- After that clue, if another *Referential Discard Clue* touches slot #5,
- There is only one newly touched card.
- There is no unclued card to right of slot #5.
- Therefore, this clue indicates a *Locked Hand*.
</details>

### Focus and Target

Explaining referential clues another way:
- The *Focus* of a clue is defined as follows: if only the *Focus* were touched, the clue would have the same meaning.
- The *Target* of a clue is the card told to play/discard.

For *Referential Play Clues*:

- The *Focus* of a *Referential Play Clue* is the leftmost *newly* touched card to the right of chop if there is one, otherwise it's the leftmost *newly* touched card.
- In the common case where slot #1 is chop, this means that the *Focus* is the **leftmost *newly* clued card not on slot #1** if there is one, **otherwise it's slot #1**.
- The *Target* of a *Referential Play Clue* is the ***previously* unclued card to the left of the *Focus***, wrapping around if necessary.
- As a consequence, when chop is on slot #1, the only way to give a *Wraparound* is to give a color clue that newly touches **only** slot #1. If the clue touches any other previously unclued card, it will be focused on that card instead, so it will not be a *Wraparound*.

For *Referential Discard Clues*:

- The *Focus* of a *Referential Discard Clue* is a bit more complicated&mdash;although the *Focus* is usually leftmost, a *Referential Discard Clue* never means to discard one of the cards it touches.
- For example, a *Referential Discard Clue* that newly touches two consecutive cards does **not** target the right card of the two consecutive cards. That card is touched by the clue. The *Target* is actually the previously unclued card to the right of that card.
- The *Target* of a *Referential Discard Clue* is the ***previously* unclued card to the right of the *Focus***. If there is no card to the right of the *Focus*, then the clue has no target and it means to ***Lock***.
- The *Focus* of a *Referential Discard Clue* is the leftmost newly touched card that's on chop or to the right of chop, ignoring cards whose *Target* (that is, the previously unclued card to the right) is also newly touched. (*Referential Discard Clues* which only touch cards to the left of chop are currently ill-defined.)
- In the common case where slot #1 is chop, this means that the *Focus* is the **leftmost *newly* clued card such that the previously unclued card to its right isn't newly touched**.

## Advanced Conventions

### Reclues

A clue that only touches already-clued cards is called a *Reclue*. Clues that reveal that an already clued card is immediately playable or trash give a safe action and thus should not be treated as a *Referential Clue*. But what if a reclue doesn't reveal any safe action?

Then, it indicates a **potentially delayed** play on one of the cards that it touches. Specifically, the clue is either
- a *Finesse* on the fully revealed card that makes the most sense;
- or a potentially delayed play on the leftmost touched card that remains unknown.

### Finesses and Prompts

- *Finesse*: When a clue means to play a card, but the team can see that it's not yet playable, the clue promises the team that they can play the "connecting cards" (the cards necessary to make it playable) without further clarification.
- We say that the players who will play connecting cards are "finessed".
- *Prompt*: If a player is supposed to play a connecting card into a *Finesse*, and they have a clued card which could be the connecting card, then they are expected to play the rightmost such clued card.
- *Finesse Position*: If a player is supposed to play into a *Finesse*, and they do not have any clued cards to *Prompt*, then they are expected to play their leftmost unclued card.
- *Finesse Positions*: If a player has already played their *Finesse Position* into a Finesse, but they still have more connecting cards to play, then they are expected to play their rightmost card that could possibly be the connecting card.
- At any given time, a player's *First Finesse Position* is their leftmost unclued card, their *Second Finesse Position* is their rightmost unclued card, their *Third Finesse Position* is their second rightmost unclued card, and so on.
- Cards that are already gotten by a previous play clue or *Finesse* are considered clued and do not occupy *Finesse Positions*. (For example, when a player is finessed twice, the new finesse will start from the leftmost unclued card, not their old *Second Finesse Position*.)
- That said, if a player is supposed to play a connecting card into a *Finesse*, but they already have a card to play from a previous clue that could be the connecting card, they should usually play the old card first to be safe.

### *Loaded Play Clues*

A player who already has a safe action (known play or known trash) is referred to as *Loaded*.

*Referential Discard Clues* cannot be given to *Loaded* players, because their chop would just reset to leftmost anyway after they took their safe action. Therefore, number clues given to *Loaded* players must mean something different.

A number clue given to a *Loaded* player means to play the leftmost newly touched card. This is referred to as a *Loaded Play Clue*.

### Good Touch Play Order

When a player has multiple cards with the same positive clue, each of which is known to be either trash or immediately playable, they are expected to:

- Discard them in right-to-left order

If not, it is a *Chop Move* if you are using expert conventions, see [Trash Order Save](https://hackmd.io/Ui6LXAK3TdC7AKSDcN20PQ?both#Trash-Order-Save-Always-on-next-player).

- Play them in left-to-right order

If not, it calls for a priority play if you agreed on it, see [Priority](https://hackmd.io/Ui6LXAK3TdC7AKSDcN20PQ?view#Priority).

Thus, 1s are played left to right at the beginning of the game. If not, see [1s order Save](https://hackmd.io/Ui6LXAK3TdC7AKSDcN20PQ?both#1s-Order-Save).

Note that if cards are not exactly known playable and you could bomb a useful card, you play from right to left (Prompts, Anxiety, Priority) as older cards always have more info.

(Pink): Rank-clued cards are played right-to-left in pink.
It makes it as likely as possible that we can get a single card to play because rank-clued cards can be unplayable pink cards.
If it's on the left side, we can give a color clue, and if it's on the right, we can give a rank clue.

### *Zero Clue State*

When the team goes to 0 clues, it enters a *Zero Clue State*. During a *Zero Clue State*, all discards must come from cards that were in hands when the state was first entered. In order to exit the *Zero Clue State*, a player must take an action while there is 1 clue token.

### Discards of known cards (Gentleman's etc.)

If a player discards a card when they could have played it instead, it means that another player has it in the **rightmost** possible position, possibly stacked behind other playable cards.

If the card is stacked behind other *unplayable* cards, a **fix clue** must be given before the target player has an opportunity to start bombing.

If the card was useful but not immediately playable, it does not promise position.

<details>
<summary><b>Examples (Click to show)</b></summary>

- Alice discards a playable g3. Bob's hand is unclued, and he does not see a g3 in anyone else's hand. He plays slot 5.
- Alice discards a playable p2. Bob's hand is `x x [p] x`, and he does not see a p2 in anyone else's hand. He plays slot 3, because slot 4 cannot be purple, since it must have been held when the purple clue was given to slot 3!
- Alice has a known playable blue 1 and Bob's hand is completely unclued: `r5 b5 y5 b1 g1`. Alice is allowed to toss her blue 1, since the blue 1 goes to the rightmost slot in Bob's hand who will play it and continue "digging" to the left until he finds the promised card.
- Red 2 and Blue 2 are played on the stacks and nothing else. Alice has a known playable blue 3 and Bob's hand has three 3s clued: `g2 [y3] [b3] [r3] g5`. Once Alice tosses her blue 3, Bob is allowed to immediately start playing his clued 3s (which match the discarded blue 3) from right to left until the blue 3 is found.
- Suppose Red 2 and Blue 2 have been played, as before, and Alice discards a known playable blue 3. Cathy's hand has three 3s clued: `g2 [b3] [r3] [y3] g5`. Bob must give a yellow fix clue to Cathy before she has the opportunity to bomb the yellow 3. (A blue clue is also possible but worse in this particular situation since it stops the red 3 from playing for free.)
</details>

### Stalling Situations

When all of a player's cards are saved and the player does not have a known play, the player is referred to as *Locked*.

When a player has 8 clues or has a *Locked Hand*, they must give a clue. Giving an obligatory clue is referred to as "stalling", and these situations are referred to as "stalling situations".

In stalling situations, referential play clues or discard clues are interpreted as normal (including *Playful Positionals*).
If there is no good play or discard clue to be given, then:
- A *Reclue* does not promise that any of the touched cards are playable. (It's just a Fill-in)
- A number clue that would normally *Lock* another player is ignored instead. (It's just a Non-Locking Stall)
- A number clue that would be a *Loaded Play Clue* is ignored instead. (It's a Non-Loaded Stall)

As a last resort:
- A *Hard Burn* that does not give any additional info

Note that if a *Hard Burn* is given when a better stall clue was available, it is treated as a *Play Clue* (often a finesse or bluff).

### Direct play order

When a player receives a referential clue which also identifies a touched card as exactly playable (either by good touch or by filling in a card as playable), then they are expected to play that card first and complete the blind play after.
Note that this allows for *Reverse Finesses/Prompts*.

### Useful Discard

When the team allows a useful card to be discarded, and you don't see it in anyone else's hand, you can suspect that you hold the other copy. You can be certain that you hold the other copy if
- The useful card was clued and they had a safe alternative (like discarding their chop or playing a card)
- The useful card was clearly "called to discard"
- For example, it was targeted by a discard clue and the receiver's chop was not useful prior to the clue
- For example, Alice gave the clue that Bob would have given, forcing Bob to discard

When a player is *Finessed* for a card, if they have elimination for that card, they should play the rightmost possible position for that card as a *Prompt*.

If only one card could be the copy, that card is considered clued for the any conventions that consider cluedness, including referential play clues, discard clues, finesse positions, and playful positionals.

<details>
<summary><b>Examples (Click to show)</b></summary>
- Alice gives a play clue to Cathy, and Bob discards a useful red 4 on chop.
- Bob was clearly "called to discard", because Alice could have discarded and let Bob give the play clue instead
- Cathy does not see red 4 in anyone else's hand, therefore she knows that she holds a red 4. The whole team is on the same page that Cathy has *Elimination Notes* for the red 4.
- All 1s played on the stacks. Alice's hand is r1 x [g3] x. She has permission to discard r1, but chooses to discard g3 instead. Bob doesn't see g3 in anyone else's hand, and marks g3 elimination on his hand.
</details>

### Trash Push

When known trash is clued with number, it means to play the card to the left, just like with color. It does not make sense as a *Referential Discard Clue*, because cluing number on the card to the left as a *Referential Discard Clue* is more efficient.

(Null): Trash clues with number can be *Direct Discard Clues*, simply indicating to discard the touched cards.

## Expert Conventions

### *Playful Positional*

When a bad number clue is given and an intervening player sees that a play clue could have been given instead, they react by blind-playing a card that signals to the clue receiver which slot to play.
<details>
<summary><b>Example (Click to show)</b></summary>

- All 1s played. r2 played.
- Cathy holds y2 g2 b2 p2 r3
- Bob expects Alice to clue yellow to Cathy
- If Alice clues 3s to Cathy instead, it will be a *Playful Positional*.
- If Bob plays 1st finesse (slot 1), Cathy will play 1 space to the left of the clued card (slot 4)
- If Bob plays 2nd finesse (slot 5), Cathy will play 2 spaces to the left (slot 3)
- If Bob plays 3rd finesse (slot 4), Cathy will play 3 spaces to the left (slot 2)
- If Bob plays 4th finesse (slot 3), Cathy will play 4 spaces to the left (slot 1),
- If Bob plays 5th finesse (slot 2), Cathy will play 5 spaces to the left (slot 5 wrapping around)
</details><br/>

The general process is as follows:

1. The *Focus* of the *Playful Positional* is the leftmost newly touched card, except that chop has lowest precedence. (Similar to *Referential Play Clues*)
2. The *Target* of the *Playful Positional* is the leftmost previously unclued playable card in Cathy's hand.
3. Bob counts the cards from the *Focus* to the *Target*, moving left, skipping previously clued cards, and wrapping around if necessary.
4. Bob plays the finesse position corresponding to the number of cards. (For example, immediately to the left of the *Focus* would correspond to the *First Finesse Position*)

If Bob has an unknown clued card, and Alice's clue would be reasonable if Cathy's playable was a duplicate of it, Bob should not react.

If Bob sees that the *Playful Positional* given to Donald could be on Cathy, they should let Cathy play into it.

In 5 player games however, the *Playful Positional* is always on the next player without a safe action.

### Ejections - Discharges - Charms - Blasts

Those moves can only be done in [*Bluff Seat*](https://hanabi.github.io/docs/level-10#the-bluff-seat).

When a 2-away card is pushed, it cannot be a double finesse, because Cathy will always assume immediately playable over a reverse finesse, so she will bomb before Bob has a chance to play the second card. Instead, this signals an *Ejection*.
The team should now treat the pushed card as clued. (Add a `[clued]` note to the card to make it appear as clued).

Here is a table to let you know what should happen with a hand of 5 cards :

| Target | Name | Finesse Position | Slot if unclued |
| ----------- | --------- | ---------------- | --------------- |
| 1-away | Finesse | 1st | 1 |
| 2-away | Ejection | 2nd | 5 |
| Known Trash | Discharge | 3rd | 4 |
| 3-away | Charm | 4th | 3 |
|4-away| Blast | 5th | 2 |

With only 4 cards: 3-away and 4-away both cause a Charm (slot #2 if unclued).

### Direct Play Promise

When a direct play clue is given with number touching only chop, it promises that the unclued card to the right is trash. Otherwise, a color clue must be given.

(White/Null): The card to the right is known to be either White/Null or trash.

### Priority

We use the same logic as H-Group for priority. See [H-group Priority](https://hanabi.github.io/docs/level-20).
- *Priority Prompt*: gets the rightmost card with color or rank match
- *Priority Finesse*: gets the rightmost unclued card, can be layered
- *Priority Bluff*: when in *Bluff Seat*, you can *Bluff* the rightmost unclued card or *Prompt* a card (in a multicolor variant). The clue gets nothing more.

### Unknown Trash Push Ignition

If a trash push is available and a color clue which bad touches is given instead, Bob must play his *First Finesse Position* to tell the receiver of the clue that the *Focus* of the color clue is trash. At first it will look like a *Finesse* has occured, but after the pushed card plays, it will become clear that the only reason Bob played was because the *Focus* of the color clue was trash.

<details>
<summary><b>Example (Click to show)</b></summary>

Here 2 is available as a trash push (r2 is globally known) but purple is given (p4 and p5 were already gotten) thus Bob blind plays his finesse position. This confirms to Cathy that their purple 2 is trash.


She then can play #2 or discard #3

</details>

### Free Choice Ignition

When Alice has free choice between a *Color Push* and a *Trash Push* to get a card to play, a rank clue always triggers a play from Bob's *First Finesse Position*.

<details>
<summary><b>Example (Click to show)</b></summary>

Here Alice could clue y or 2. Both give known trash info to Cathy. Alice chose 2 over yellow meaning she wants to trigger a Free Choice Ignition.


- Bob blind plays p3
- Cathy plays r5
</details>

### 1s Order Save

1s are supposed to play from left to right. If a 1 plays out of order, this *Chop Moves* the next player without a safe action, and they cannot discard on their next turn.

<details>
<summary><b>Example (Click to show)</b></summary>

In a 5 player game
Alice has 3 playables 1s on #1 #3 #4
Bob is busy :

- Playing #1 does not cm anyone. Game goes on as usual.
- Playing #3 cm's Cathy. She is not allowed to discard this turn, her new chop is the second leftmost unclued card of her hand.
- Playing #4 cm's Cathy twice. She is not allowed to discard this turn, her new chop is the third leftmost unclued card of her hand.
</details>

Pink: 1s need to be played in order.

### Trash Order Save

(Always on next player)

The expected discard order of clued trash is right-to-left.

If trash other than the rightmost is discarded, the next player should save some cards on their chop. The specific number of cards is determined by which trash card is discarded. This skips over loaded players, since all their cards are saved anyway.
If all players are loaded, this indicates a trash card on the next player's hand. (Imagine *Chop Moving* the next player in the future.)

<details>
<summary><b>Example (Click to show)</b></summary>
Alice has four known trash. Bob is not loaded :

- If Alice discards her rightmost trash, it means nothing.
- If Alice discards her second-rightmost trash, Bob will save his chop.
- If Alice discards her third-rightmost trash, Bob will save his chop and his next unclued card.
- If Alice discards her fourth-rightmost trash, Bob will save his chop, and his next two unclued cards.

Alice has four known trash. Everyone is loaded :

- If Alice discards her rightmost trash, it means nothing.
- If Alice discards her second-rightmost trash, Bob's leftmost unclued card is now kt.
- If Alice discards her third-rightmost trash, Bob's second-leftmost unclued card is now kt.
</details>

---

## 2-Player Specific Conventions

### Starting hand stalls (Basic)

On the first turn in 2p, clues work as normal, with one exception: Number clues touching rightmost are treated as *Starting Hand Stalls*. When Alice gives a *Starting Hand Stall* to Bob, Bob must give a clue on the next turn. After Bob clues, his next discard will be his leftmost unclued card, unless Alice gives a second clue. If Bob's clue touches Alice's rightmost card, it is also treated as a *Starting Hand Stall*.

Brown: A brown clue touching rightmost is also considered a *Starting Hand Stall*.
Null: Starting hand stalls with a null-card in slot 5 are impossible. In the rare scenario no legal clue is available, you could use a t1 bomb.

### No-Info Double Bluff (Basic)

If a clue is given that gives no new positive information (i.e. touches only already clued cards and does not fill any of them in), it signals a double bluff (a blind-play from slot 1 and a blind-play from slot 2).

This applies even if the reclued card could be playable; players are expected to fill in clued cards to get them to play.

Null: if slot 1 is a null card, do not continue.

### Unlock Promise (Advanced)

When your partner is locked, and pace is >2, it is always better to discard known trash than to play a card that does not immediately unlock your partner. Therefore, if you play a card that looks like it might unlock your partner instead of discarding known trash, you promise that the connecting card is in the oldest possible position in your partner’s hand. If there’s no possible connecting card, you simply communicate that the oldest possibly playable card is indeed playable.

### Locked hand stalls (Advanced)

Following from unlock promise, it is important that a locked player is cluing playable cards such that they are fully-known. Therefore, we use a different stalling convention for locked players in 2p.

Specifically, we play with color stalls:
- Number is save as normal
- Color touching slot 1 means to play slot 1
- Color elsewhere means to discard slot 1

Null/Brown/White: With white/null a color reclue touching the leftmost previously-color-touched card is a play of a white/null card. In brown/null, rank reclues touching the leftmost previously-rank-touched card are a save of a brown/null card.

### Bomb Lock (Advanced)
Attempting to play a card that you have permission to discard tells your partner that they are locked. Players should prefer to use this method when possible, so if you choose to use a clue to communicate a lock when you could’ve safely bombed to do so, you usually imply that you expect your partner to make a sacrificial discard. Note that sometimes you do not have permission to discard any card.

Copied from the [main sieve doc](https://hackmd.io/@sjdrodge/S1pRVuxsu#Bomb-Lock).

### Zero Clue Safety Promise (Advanced)

A more contextual zero clue convention. See [the main sieve doc](https://hackmd.io/@sjdrodge/S1pRVuxsu#Zero-Clue-Safety-Promise) for more details.

### Permission to discard (Expert)

Suppose it is Alice's turn, and it is not common knowledge that Bob has any safe actions. If Alice then takes an action which does not (up to common knowledge) give Bob a safe action, Bob's chop is said to have "permission to discard" (or PTD). If Bob's chop has PTD, and Alice gives him a play, then the play will usually happen first. Later, when it is time for Bob to discard, he will still discard the card with PTD, regardless of whether it is the leftmost untouched card in his hand. This is because a card that has had PTD is, on average, a better discard than a newly drawn card. If Bob's PTD card is not actually trash and is about to be discarded, Alice can still save it by giving a discard clue.

<details>
<summary><b>Example 1(Click to show)</b></summary>

- r3 played
- Alice: `x p5 x x x`
- Bob: `x [r5] x x x`

1. Alice discards slot 1, giving Bob permission to discard slot 1. Alice draws r4; `r4 p5 x x x`
2. Bob clues purple to Alice
3. Alice plays red 4, and draws trash
4. Bob plays red 5, but recognize that the card on his chop was saved unwillingly by Alice.
5. Alice discards
6. Bob discards slot 2

Or alternatively, if Bob's chop actually was useful

5. Alice clues 4s to Bob `x [4] x x x`
6. Bob knows that his chop was slot 2, so this is just a save clue on his chop, and discards slot 1.
</details>

<details>
<summary><b>Example 2 (Click to show)</b></summary>

- r3 played
- y2 played
- g5, b5 played
- Alice: `r4 p5 x x x`
- Bob: `x [r5] x x x`

1. Bob clues purple to Alice
2. Alice looks at stacks, sees the card told to play could be r4 or y3 and plays it. This gives Bob ptd because it was not common knoweldge that Alice was giving him a play.
3. Bob plays red 5.
4. Alice discards her slot 1.
5. Bob discards his slot 2.
</details>

<details>
<summary><b>Example 3(Click to show)</b></summary>

- r3 played
- y2 played
- g5, b5 played
- Alice: `r4 p5 x x x`
- Bob: `x [r5] y3 y3 x`

1. Bob clues purple to Alice
2. Alice looks at stacks, sees the card told to play must be r4 and plays it. This still gives Bob ptd because it was not common knoweldge that Alice was giving him a play. Alice knew she was giving Bob a play, but Bob didn't know Alice knew that.
3. Bob plays red 5.
4. Alice discards her slot 1.
5. Bob discards his slot 2.
</details>

---

## Experimental Conventions

### Cooperation Clues

There's this concept of "cooperation" with sieve-style saves (clues that save all cards further in one direction than the introduced card most in that direction); it sometimes takes two clues to save an entire hand, so we can choose a conventional sequence of clues such that following or deviating from that sequence distinguishes between a) Alice inviting Bob to save Cathy and b) Alice putting on Cathy's chop another copy of one of Bob's cards.

A cooperation clue must follow this priority list; otherwise, it will be confused with a different-hand-dupe signal.
1. Put a critical on chop (such that one more clue would still lock)
2. Touch rightmost unclued (one more clue will always lock, since at least two cards have been touched by this clue)

The reason that 2 clues are required to lock is that there is a card with the same rank as rightmost, so cluing the rightmost card reveals to the receiver the possible intent of a cooperation clue. That revelation could be important to Cathy when Bob declines to lock her because the card now on her chop is duped in Alice's hand.

### Focus Slide
If a pushed card is known not playable by context, you slide to the next playable card to the left.

<details>
<summary><b>Example (Click to show)</b></summary>

What should Cathy do here ?


Of course the red clue is a push on the slot 3.
But Cathy thinks for a second what card could it be ? The only possibility is u2 but she has been holding this card since the beginning of the game and noone has clued it, so why now ?
Either she drew something valuable and the team want it to be sieved, either it's a focus slide and she is expected to play slot 1 also signaling slot 3 is a null card.
In fact when she rewinds the game she sees that the team made her discard a card to save a 5 instead of making the card in slot 3 play.
Enough thinking Cathy has sufficient info to know she should play slot 1.
U2 succesfully plays Sunday, bloddy Sunday
</details>

### Duping Avoidance Strategies

Duping is not so bad in ref sieve but we try to avoid it if possible.
So when you have a clued card that could match a card in someone else's hand, it's not your job to make it play or to save it. The rest of the team should be aware of what their teammates know about their hands and act in consequence.

### Chop Position Exception

Don't save/play clue a card a player can see on the chop of one of the next player because they will try to save/play clue it themselves.

This rule does not apply to direct play clue as the player who recieves it is then following duping avoidance strategy

### Certain Finesse

If a person holds a card that have matching information for a card they call to blind play into a finesse, the called card must be exactly in finesse position.
So if Alice holds a 3 and try to finesse blue 3 by cluing blue 4 in Cathy's hand. Blue 3 must be in Bob's first finesse position (unlayered)

### Layered Finesse

Layered finesses are hard to give and need extra care. The person who recieves the clue must be promised a safe action if they have to wait

### Elim Finesse

When a finesse is given for an elimed card the blind play should occur from the rightmost matching card.

### Bluff

Bluffs are tricky with referential play clues so there are only 3 types of bluff that we allow :
- Reclue Bluff : The bluff target is known
Recluing a 1 away card can lead to a bluff if there is a mismatch between the blind play and the target

*There is still some debate if these types of situation should call for blind plays until the promised card is played as a layered finesse. What is sure is that a first blind play has to happen !*

- Transparent Bluff : Leads to blind play a 5
Of course it's a bluff. The clue reciever should mark the card as a 1-away.
- Known Color Bluff : The pushed card is color clued
When #1 is pushed with the same color as #2, the color of the pushed card is known, thus allowing for a bluff with a clear mismatch of color.
- Color Mismatch Bluff : The blind play is the same colour as the one used to push
When a blind play is not of the same colour as the pushed card it's always a bluff.

Those bluffs can only be given in [Bluff Seat](https://hanabi.github.io/docs/level-10#the-bluff-seat)

### Out of Order Finesse

To be discussed : after a fix do we play leftmost or rightmost ?

### Pink specific

Due to Good touch play order : When a rank direct play clue does not identify all the card as not pink we play them right to left, e.g. 1s in the beginning.

Rank Tempo Clue :
When a rank tempo clue is given on globally known pink cards there are 2 options :
- It touches a unique card --> Pink promise (The card is exactly this rank)
- It touches only pink cards --> Positional Play Clue (play slot matching rank)
- It touches not only pink cards --> [Referential Discard Clue](https://hackmd.io/Ui6LXAK3TdC7AKSDcN20PQ?view#Referential-Discard-Clues)

Double-Edged Pink Clue :
If Alice misranks a globally known playable pink card in Cathy's hand, it is a signal for Bob to play this slot, Cathy can then play their pink card.
It's is possible to perform a double-edged pink clue on a non globally known pink card as long as a Playful Positional Interpretation is not possible (e.g. when there is no previously unclued card in Cathy's hand.)

Fix clue on a misranked dark pink :
The basic fix clue on a misranked pink is a pink clue, e.g. Multiple ones have been clued in the first round. A pink clue on a 1 that is going to play (rightmost in pink, remember) means that this card is not a 1.
A different rank clue conveys a fix and a referential discard clue, a reclue or a loaded play clue.

This convention is maybe not working for normal pink as there are more pink cards. To be discussed.

### Omni specific

Rank direct play clue play right to left.

Omni tempo clues are positional (colour signals the slot like [Mud Clues](https://hanabi.github.io/docs/variant-specific/muddy-rainbow-cocoa-rainbow/#mud-clues), rank signals the slot)
When it's on Bob it's always a direct play clue.
When it's on Cathy
- Colour calls for a finesse (can be layered)
- Rank clues work like [EDCB](https://hackmd.io/Ui6LXAK3TdC7AKSDcN20PQ?#Ejections---Discharges---Charms---Blasts) (if a 2 away card is in the targeted slot, Bob ejects etc.)

<details>
<summary><b>Example (Click to show)</b></summary>

Bob just recieved this 3 clue. Initially this would indicate he holds o1 in slot 3 as a positional clue.
But Alice plays u2 from slot 5 next (ejection).
What should now happen ?
Bob marks his slot 3 as o3 (as a 2-away) and proceeds with his life.
If Alice would have played b1 from slot 3 (charm) then Bob would mark o4.
slot 2 (blast) would be o5, slot 4 (discharge) dupe omni, slot 1 (finesse) would be o2.
</details>

### Null specific

No Direct Play promise
Trash pushes are off (except if chop is revealed to be trash)
Playful positional targets playable null cards over leftmost Playable

### Funnel specific

A 4 clue is a lock as it touches all cards and reveals the 5s.

A 5 clue is a save to chop. All previously unclued cards should be marked unclued (using "x" on the note) and then proceed game normally. The player's new chop is now right to previous chop

### Ambiguous Tempo Clue

When 2 cards cannot be distinguished by empathy :
- A colour tempo clue means play leftmost.
- A rank tempo clue means play rightmost.

### Flexible Targeting: Balance Clues

*This convention overlaps with [Ejection, Discharge, Charm and Blast]([https](https://hackmd.io/Ui6LXAK3TdC7AKSDcN20PQ?both#Ejections---Discharges---Charms---Blasts)), choose your weapon.*

When a color clue is given to Cathy which seems to target a card which cannot become playable by Cathy’s turn, the clue is actually targeting some other playable or trash card in Cathy’s hand. Bob will react with a blind play or blind discard to indicate the target of the clue to Cathy.

1. If Cathy has multiple playables, the target is the leftmost playable card that Bob can signal
2. If Cathy has no playables, the target is the rightmost trash (counting duplicates as trash, excluding the original clue target)
3. Bob counts the cards in between the focus of the clue and the target, moving left, skipping previously clued cards, and wrapping around if necessary
4. To indicate a playable card to Cathy, Bob discards the discard position corresponding to the number of cards (e.g. 2 cards to the left = 2nd discard position = 2nd unclued card from the left, often slot 2)
5. To indicate a trash card to Cathy, Bob plays the finesse position corresponding to the number of cards (e.g. 2 cards to the left = 2nd finesse position)

Note:
- A balance clue always results in 1 play and 1 discard.
- This only applies if the initial target of the clue did not make sense as a play clue, finesse, or prompt. This means that if Bob blind plays chop, Cathy will see it as a finesse and will not think that the targeted card is trash.
- This can be thought of as an extension of normal referential play clues. If Bob discards chop, that indicates to Cathy to play the first candidate-target, which is exactly what we would normally expect. The only difference is that the first candidate-target cannot be trash and can be used to finesse/prompt instead.

### Flexible Targeting: Assisted Discards

When a number clue is given to Cathy which seems to target a useful card to be discarded or locks Cathy, Bob should wonder:

- Could a play clue have been given to Cathy instead? -> Playful Positional
- Could I have another copy of the targeted card? -> Elimination
- Was there no better discard or tempo clue that could be given?

If none of these are true, the clue is actually targeting a different card in Cathy’s hand and Bob must react with a blind discard to indicate the target of the clue to Cathy.

1. If Cathy has multiple trash cards, the target is the rightmost trash (counting duplicates as trash)
2. If Cathy has no trash cards, the target is the least valuable card (farthest from playable/highest) using rightmost as tiebreaker
3. Bob counts the cards from the original target of the discard clue to the actual target, moving right, skipping previously clued cards, and wrapping around if necessary
4. Bob discards the discard position corresponding to the number of cards. For example, 2 cards to the right (2nd candidate in Cathy’s hand) = Bob’s 2nd discard position

Note:
- Cathy is always given a safe discard.
- Counting to the target is to the right.
- For this counting the original target = 1, so if Bob discards chop then Cathy will discard the original target.
- Newly clued cards can be targeted.
- If the clue initially locks Cathy, count as if the original target had wrapped around to her former chop.

### Playable Number Promise (Pink/Omni/Reversed)

When a number clue is given touching new cards, and all of the (non-reversed) cards of that number are playable, but the cards would not be assumed playable from Good Touch, the touched cards are expected to play right-to-left due to *Playable Number Promise*.

(Reversed): However, if a number clue is given touching a single card on chop, then a *Referential Discard Clue* should still be entertained.

### Direct Number Discard Clue

Normally when known trash is clued with number, it's a Trash Push, because it does not make sense as *Referential Discard Clue*, however it does make sense if there were at least 3 cards needing a save and you couldn't give a *Referential Discard Clue* to discard the fourth card.

Therefore, if there are at least 3 unclued cards to the left of a known trash clued by number, it's a *Direct Number Discard Clue*, which saves all cards to the left of the known trash.

Added by hakha3

### Loaded Chop

This convention defines a new way of determining chop, instead of always discarding leftmost unclued.

- Your chop starts out as the leftmost card.
- When you receive a *Save Clue*, if there is an unclued card to the right of the focus, it becomes your chop.
- When a clue gives you an immediate play, you no longer have a chop.
- When you draw a card, it becomes your chop if you do not already have a chop.

Example:
1. First turn of a 2p game
2. Bob: `r1[On Chop] b1 y5 x x`
3. Alice clues 1s to Bob `r[1] b[1] y5 x x`. Bob erases his On Chop note. He does not write a new On Chop note because this 1s clue gives a known playable card.
4. Bob plays r1 and draws r2 `r2[On Chop] b[1] y5 x x`
5. Alice clues yellows to Bob `r2[Play Clued] b[1] [y]5 x x`
6. Bob plays b1 and draws a second copy of r1 `r1[On Chop] r2[Play Clued] [y]5 x x`
7. Alice discards
8. Bob plays r2 and draws b5 `b5 r1[On Chop] [y]5 x x`
9. Alice discards
10. Bob discards r1 from slot 2

Note:
- *Loaded Play Clues* are still on. We expect to wait until a player has no safe actions before giving a save clue, because it gives the most options for which card to discard.
- When a *Save Clue* is given and the clue receiver already has a chop, the clue works a little differently. We think of the hand as though the chop card were in the leftmost position.
- If the clue touches the previous chop card, then the chop becomes the leftmost unclued card.
- Otherwise it means that your new chop is the card right of the focus, skipping clued cards and the previous chop card.
- When determining the focus of a *Referential Play Clue*, the chop card should not be treated specially. All the rules that refer to the chop card in that convention should be interpreted as though they refer to the leftmost unclued card instead.

<details>
<summary>Analysis (Click to show)</summary><br/>

Advantages:
- Allows better planning. You know whether you're going to have to clue somebody's hand without knowing what card they're going to draw
- Cards that are not gotten to play ASAP are less likely to be playable, and therefore more likely to be trash
- Zero Clue State + Permission To Discard conventions practically come for free

Disadvantages:
- in 3p+, cards are less likely to be duplicates of cards that get played while they're in the hand, so slot 1 may be more likely to be trash than the On Chop card
- it may add complexity
- it conflicts with the Stacked Clues (2p) convention

Let's go back to step 4 of that example, and assume that the next 3 cards that Bob will draw are r2, b5, and b1 in some order. Let's consider all six orders with and without the Loaded Chop convention. For the purposes of this analysis, let's also assume that the clue count is 5 instead of 7, so that 8 clues isn't a concern.

Assuming Alice's strategy in the current convention is to play clue red 2 eagerly: In 3/6 cases, Loaded Chop gained a clue token. In 2/6 cases Loaded Chop lost a clue token.

Assuming Alice's strategy in the current convention is to wait before play cluing red 2: In 2/6 cases, Loaded Chop saved a clue token. In 2/6 cases Loaded Chop lost a clue token. In 2/6 cases, Loaded Chop allowed Bob to gain more information before having to give Alice a clue.

Loaded Chop is therefore better than either strategy (in this particular deck where the next three cards are trash, playable, and critical in some order). In a real deck, playables and trash are more likely to be drawn than criticals, so this analysis may be skewed.

- r2, then b1, then b5
- Loaded Chop: Alice play clues red 2, Bob plays b1, Alice discards, Bob plays r2, Alice discards, Bob discards b1
- Current convention: Alice has a difficult decision between play cluing r2 and discarding.
- Alice play clues red 2, Bob plays b1, Alice discards, Bob plays r2, Alice clues 5s, Bob discards b1
- Alice discards, Bob plays b1, Alice discards, Bob discards, Alice clues yellow, Bob plays r2
- r2, then b5, then b1
- Loaded Chop: Alice play clues red 2, Bob plays b1, Alice discards, Bob plays r2, Alice clues number on slot 1, Bob discards b1
- Current convention: Alice has a difficult decision between play cluing r2 and discarding.
- Alice play clues red 2, Bob plays b1, Alice discards, Bob plays r2, Alice discards, Bob discards b1
- Alice discards, Bob plays b1, Alice clues yellow, Bob plays r2, Alice discards, Bob discards b1
- b1, then r2, then b5
- Loaded Chop: Alice discards, Bob plays b1, Alice discards, Bob discards b1, Alice clues yellow, Bob plays r2
- Current convention: Alice discards, Bob plays b1, Alice clues 2, Bob discards b1, Alice clues red, Bob plays r2
- b1, then b5, then r2
- Loaded Chop: Alice discards, Bob plays b1, Alice discards, Bob discards b1, Alice clues blue, Bob plays r2
- Current convention: Alice discards, Bob plays b1, Alice clues 5, Bob discards b1, Alice clues yellow, Bob plays r2
- b5, then r2, then b1
- Loaded Chop: Alice discards, Bob plays b1, Alice clues blue, Bob plays r2, Alice discards, Bob discards b1
- Current convention: Exact same line
- b5, then b1, then r2
- Loaded Chop: Alice discards, Bob plays b1, Alice clues 5, Bob discards b1, Alice clues yellow, Bob plays r2
- Current convention: Alice discards, Bob plays b1, Alice discards, Bob discards b1, Alice clues blue, Bob plays r2
</details><br/>

Added by @timotree3. Acknowledgement to @sjdrodge for inspiration for this convention.

### Discard Wraparound

The current Basic Convention for *Referential Discard Clues* says

> A *Referential Discard Clue* means to discard the unclued card to right. \[...\] If there is no unclued card to the right, then the clue means not to discard *anything*. (*Locked Hand*)

The *Referential Discard Clue Wraparound* redefines this as follows:

- If there is no unclued card to the right, then the clue means to discard the leftmost unclued card. (Wraparound)
- However, if a *Referential Discard Clue* could mean to discard the card that was already on chop, that would be a waste of a clue, and it instead means not to discard *anything*.
- (This is known as a *Lock Clue* or a *Locked Hand*)
- For example, if slot #1 was on chop, a number clue touching only slot #5 could mean to discard slot #1, but since that's already on chop, it indicates a *Locked Hand* instead.

Example where this differs from the current convention:
- Cathy: r2 r3 r4 r5 b2
- Suppose Alice clues 4s to Cathy putting the r5 on chop
- In the current convention, Bob can clue
- 2s to lock Cathy
- 5s to put b2 on chop
- 3s is nonsense (maybe a play clue on the 3?)
- In the proposed convention, Bob can clue
- 2s to put r3 on chop
- 5s to put b2 on chop
- 3s to lock Cathy

---

## 2-Player Experimental Conventions

### Stacked Clues

Giving a clue to someone who already has a play is weird because normally you would wait and give a chance to choose to sieve. In order for it to be worthwhile it should either:

- Get 2+ actions
- Give the partner a fully known play so they can make better decisions
- Be a normal referential clue that would've become unavailable (because it touches slot 1)

Note: This convention applies to *stacked* clue receivers. "Stacked" means that the player has a play, while "loaded" means that they have some safe action, which could be trash.

#### Stacked Color Clues

Stacked color clues should either give a fully identified play or be impossible to give later.

- SCC touching slot 1 are referential as normal
- SCC filling in the exact identity of an already-gotten playable is referential as normal
- Example: Cluing green to Bob `r1 g[1] g5 x x` calls for red 1
- Otherwise, it is a direct play clue, focused on the card that makes the most sense

#### Stacked Number Clues

We agree that stacked number clues trigger a slot 1 play and a play of another previously unclued card. The precise mechanics are as follows:

- If the clued card can be directly playable, then you play the clued card followed by slot 1
- If the clued card cannot be directly playable, then you play slot 1 followed by the card to the left of the clued card

If the stacked number clue touches only slot 1, then it is just a loaded play clue on slot 1 and unless it's a finesse, promises that slot 2 is trash

Added by @timotree3. Acknowledgement for @melwen for collaboration in coming up with this exact configuration.

### Reclue Discard Clues

When a reclue is given revealing a 2-away non-critical 4, it means to discard a clued card, instead of being a play clue.

### Contagious Discards
Suppose all of the following conditions hold:
- Alice has ptd or kt as well as a common knowledge playable.
- Bob has ptd and/or has a common knowledge playable (possibly through Alice's playable).

Then Alice discarding promises Bob an additional discard. The additional discard is his leftmost untouched card that was not chop-moved and also does not have permission to discard. Alice playing chop-moves the card that would have been given ptd.

### Loaded Rank Play Clues
A rank clue newly touching a card given to a loaded player is a refential play clue. It refers to the previously-untouched card to the right of a newly-touched card, biased rightward in hand when multiple cards are referred to.

This is to handle situations where cards rightward in hand can be hard to tell to play via color play clues. It is also the case that in trying to acheive good touch plays, some cards (usually 2s and 3s) will benefit more from rank info than color info while others (usually 4s and 5s) benefit more from color info than rank info.

This also diversifies the info on the clue-reciever's hand: cards positively touched with color do not benefit from additional color info but do benefit from (positive and negative) rank info.

Conflicts with the Stacked Clues Convention.

#### Quasi-loaded rank play/discard clues.
A rank clue to a player with ptd is a discard clue (revoking ptd) if it would be moving the discard leftward from the ptd and a loaded play clue if it cannot be interpreted as a discard clue to a card left of the ptd.

### No-info Two-card Plays

If a clue touches no new cards and does not fill any of retouched cards in, it promises two plays. The first is always the first finesse position. If this play could connect to a retouched card, the leftmost of these play next (as a no-info finesse), otherwise the 2nd-to-leftmost untouched card plays (as a no-info double-bluff). Since no-info finesses are expected over single-card bluffs, giving a bluff can yield information on the playability of other touched cards. If the clue reveals negative info on other cards indicating a good touch play, this play should occur ASAP but does not count towards the two play requirement.

Conflicts with No-info double bluffs.

### Elimination Notes PTD Exception

If Alice has elimination notes for a playable card in multiple locations, one of which is her chop, and it is her turn, the playable is promised to not be her chop card. If that leaves only one location for the playable, the play is called for and her chop does not have ptd; it passes through the sieve for free. Additionally, this can be a bluff: if the play is not the elimination noted card, the card that was chop is promised to be the elimination noted card. H-group has a very similar convention.

### Toxic Referential Play Signals

If a referential play signal is given to a card which (for explicit/contextual reasons) cannot be playable, the card is skipped and the play signal refers to the next previously untouched card, and so on until it finds a potential playable. If none could be immediately playable, we next consider the possibility of a self-prompt-into-playable.

### Good Enough Clues

If the empathy + good touch value of a clue provides 2+ safe actions to an unloaded player, does not tell chop to discard, and it is clear there was no conventionally-as-efficient way to call for these actions, then this clue chop moves with no further conventional meaning.

<details><summary>Example 1</summary>

See [this gamestate](https://hanab.live/replay/832719#24) for reference.

With Good Enough Clues turned on, Sodium could give purple to Hallmark turn 24, getting both of Hallmark's 2s to play and chop moving slot 1, *without also asking slot 1 to play*. This is because there is no conventional way for Sodium to ask slots 2 and 3 to play using a single clue.

With Good Enough Clues turned off, to be efficient Sodium first gave g4 ptd, then gave a toxic play signal t26. This only worked because no new cards had been played and slot 5 was empathy-unplayable.
</details>
<details><summary>Example 2</summary>

See [this gamestate](https://hanab.live/replay/843803#22) for reference.

Hallmark draws two trash 1s in the midgame, both unfortunately passing through the sieve for free. Referential discard clues do not provide any way have both discard for one clue. A trash push would only work once g5 is playable. With Good Enough Clues turned on, 1s while Hallmark is unloaded does not promise a play: it is simply pointing out two trash cards. Depending on sodium's decision on the importance of tempo, this would have been an efficient option turn 22.
</details>

### Unbelievable Lock Signal

If a lock signal is given to a player who knows they could have been told about playables, but does not know where, it is a promise that all (or maybe two?) of their touched possibly-playable cards are playable right to left.

---

## Quizz & Examples (Under Construction)

Here are (still in working progress) attempts of learning sieve more interactive

### Play Clues

- The Vanilla Direct Play Clue : What should Bob do ? 
<details> <summary>Answer</summary> Don't beat around the bush Bob, play your 1s from left to right. Notice it's saving #1 without any need to clue it. Yay! This type of clue works on 2s if every 1s are down and so on so forth.</details>

- The Vanilla Color Push : What should Alice do ? 

<details>
<summary>Answer</summary>
The clued cards pushes the card to its left. #2 plays blind. Easy peasy !
</details>

- The Wraparound Clue : What should Cathy do ?
<details>
<summary>Answer</summary>
The clued card pushes wrapping around #5 plays
</details>

- Where is The Focus ?
<details><summary>Answer</summary>
The focused card is the one closest to chop (excluding chop if it is touched) so here it's #2. You can also consider that every clued card pushes the unclued card to its left and you play the closest to chop which is #1
</details>

- Where is The Target ?
<details>
<summary>Answer</summary>
You skip the previously clued cards so #1 should play
</details>

- Stacking Play Clues :
<details>
<summary>Answer</summary>
Cards should play in the order the play clues have been given.
</details>

- Finesses and Prompts
- Prompt
<details>
<summary>Answer</summary>

</details>

- Finesse :
<details>
<summary>Answer</summary>

</details>

- A Reverse Finesse : 

<details>
<summary>Answer</summary>
This is a Referential Play Clue on #1. But Bob already has a safe action so they should play their 1s first. The pushed card could be a 2.
</details>

- Fake Trash Push Ignition : What clue should Bob give ? 
<details>
<summary>Answer</summary>

- Bob could give 5 to Cathy but it's not very efficient as Cathy would have to get g4.
- Bob could give 2 to Alice as a trash push but there is a chance it kills r5.
- Bob should clue red to Alice pushing g4 and causing a blind play from Cathy's first finesse, demonstrating Alice's red card is trash. Nice Fake Trash Push Bob !
</details>

- Edge Cases
- What does this Clue mean ?
<details>
<summary>Answer</summary>
By good touch the purple can only be a 5. So it looks like a direct play clue. But actually we use color on untouched cards only to push. Thus Bob should play #3 and wait for the team to fix if needed. If not he can safely play #4 as p5 next turn.
</details>