---
# System prepended metadata

title: Turbo v2 - a 2p Hanabi convention system
tags: [Hanabi]

---

---
tags: Hanabi
---

# Turbo v2 - a 2p Hanabi convention system

## Introduction
Turbo v2 is a convention system for specifically 2-player Hanabi. It inherits most of its structure from Referential Sieve, with one major twist: **Turbo is a discard oldest system**.

Turbo's primary innovation is the [Unloaded Chop Move](#Unloaded-Chop-Move), which essentially allows us to import the biggest benefit of discard-newest systems into a discard-oldest context. Namely, that cards on chop can be easily saved as a side effect of other clues. The result is a very strong 2p convention system that I believe outperforms all other well-known human-playable 2p convention systems as of January 1, 2026.

For those trying to learn the system from scratch, the first two sections should be sufficient to get started: [Basic Terminology & Principles](#Basic-Terminology-amp-Principles) and [Basic Conventions](#Basic-Conventions). Then when you start to run into situations that seem undefined, the [Advanced Conventions](#Advanced-Conventions) (the bulk of the document) are there to help, and are conveniently organized by topic.

The prose in this document is meant to convey the most important aspects of a convention as concisely as possible. Often, this means intentionally underspecifying conventions to make their description simpler. However, if this choice proves to be unpopular or unwieldy, it may be changed in the future. Please feel free to give feedback on any conventions you find unclear, or whose wording can be improved.

### Acknowledgements
Huge thanks to everyone who contributed (knowingly or not), to Turbo's development. The non-exhaustive list includes: **florrat**, **hallmark**, **kimbi**, **Lel0uch**, **Libster**, **pianoblook**, **piper**, **sodiumdebt**, and **timotree**.


## Basic Terminology & Principles

#### Chop
The card that a player is expected to discard once they run out of explicitly promised safe actions.

#### Permission To Discard
Usually abbreviated **PTD**. Once a player with a [Chop](#Chop) is left without an explicitly promised safe action, they gain **PTD** for the card that is on [Chop](#Chop).

#### Loaded
A player is considered **Loaded** when they already know about a safe action. [PTD](#Permission-To-Discard) counts as a promised safe action.

#### Chop Move
Whenever a card is saved without being touched by a clue.

#### Unloaded Chop Move
Giving a safe action to an [Unloaded](#Loaded) player implies that the card on their [Chop](#Chop) might be good. In this system, we explicitly [Chop Move](#Chop-Move) that card. *This is our most fundamental principle. Any situation where it doesn't apply will be explicitly noted.*

#### Good Touch Principle
Cards that have been touched by clues are generally assumed to be useful cards. See [Good Touch Play Policy](#Good-Touch-Play-Policy) for additional information.

#### Discard Precedence
All the unclued cards have a discard precedence (used for interpreting otherwise ambiguous discard clues). To rank them from highest to lowest, start with the card on [Chop](#Chop), then proceed leftwards and wrap around until you get back to [Chop](#Chop).

#### Called Cards are Clued
aka **CCC** or **Triple C**. Once a card has been explicitly instructed to either play or discard, or given [PTD](#Permission-To-Discard), it is considered clued.

#### Locked
When a player has no cards that are safe to play or discard.


## Basic Conventions

The most fundamental conventions. Enough to start playing.

### Unloaded Chop Move Principle
[See the description above](#Unloaded-Chop-Move)

### Starting Hand Chop Moves
Every card except the leftmost card in both player's hands starts [Chop Moved](#Chop-Move).

### Fill-in Focus
Any clue that directly fills in a previously clued card as [Trash](#Trash) or [Playable](#Playable) is focused solely on the filled in cards and does not trigger any conventions other than [Unloaded Chop Move Principle](#Unloaded-Chop-Move).

### Number Discards
Number clues are left-referential discard clues by default. Meaning, discard the unclued card to the left of the newly clued card. If there are multiple such candidates, discard the candidate with the highest [Discard Precedence](#Discard-Precedence) that wasn't already on [Chop](#Chop).

Notes:
- All the cards that had higher [Discard Precedence](#Discard-Precendence) than the instructed discard are [Chop Moved](#Chop-Move).
- If the only candidate is the card that was already on [Chop](#Chop), then you have no safe discards and are considered [Locked](#Locked).

### Number Plays
When all the cards of a particular number are playable (e.g. 1's at start of the game), cluing that number does not indicate a discard. Instead, it indicates that all the clued cards are playable.

Notes:
- This applies even if some of the cards matching that number have already been played.
- If you are not [Loaded](#Loaded) and one of the clued cards is on [Chop](#Chop) without having [PTD](#Permission-To-Discard), it should play first. Otherwise prefer slots 1, 5, 4, 3, 2 in that order.
    
### Color Pushes
Color clues are play clues that "push" the previously-unclued card to the left of the newly clued card. If there are multiple such candidates, play the leftmost candidate.

Notes:
- Unlike with discard clues, a card touched by the clue can be a candidate. This happens when either you have only one previously unclued card or when your two leftmost previously unclued cards are the same color.
- Cards told to play this way may be [Delayed Playable](#Playable) behind other known plays from that player's hand.


## Advanced Conventions

The rest of the conventions are organized by topic. Conventions in this section are assumed off in beginner games and on in expert games.

---

### Reclues
This section covers clues that only touch previously clued cards.

#### No-info Double Play
A reclue which does not fill in any new information calls for two plays. The first play is always the leftmost unclued card. If that card could [Connect](#Connecting-Cards) to one of the [Reclued](#Reclue) cards, the second play is the leftmost of those cards. Otherwise, the second play is the second leftmost unclued card.

Important notes:
- *[Unloaded Chop Move](#Unloaded-Chop-Move) Exception.* No-info Doubles are valuable enough and urgent enough that they should usually be given regardless of what card is on [Chop](#Chop). Therefore they do not cause a [Chop Move](#Chop-Move).
- Both plays from a No-info Double are allowed be [Delayed Playable](#Playable) behind other plays from that player's hand.

#### Negative Tempo Fill-in
If filling in cards reveals that another card is [Immediately Playable](#Playable) while at least one of the reclued cards is [Delayed Playable](#Playable), then the clue is focused solely on the filled in cards and does not trigger any conventions other than [Unloaded Chop Move Principle](#Unloaded-Chop-Move).

#### Fill-in Bluff
Filling in [Unplayable](#Playable) cards that are either [Critical](#Critical) or a **2** calls for a blind-play of the leftmost unclued card.

Note: Cards told to play this way are [Immediately Playable](#Playable).

#### Fill-in Sacrifice
Filling in [Unplayable](#Playable) cards that are neither [Critical](#Critical) nor a **2** [Chop Moves](#Chop-Move) all unclued cards and communicates a [Lock](#Locked). However, your partner will often immediately unlock themselves by discarding the clued card (or any other card).

Note: Since [Locking](#Locked) a [Loaded](#Loaded) player doesn't make sense, giving this kind of clue to a [Loaded](#Loaded) player is a [Loaded Fill-in Bluff](#Loaded-Fill-in-Bluffs) instead.

#### Direct PTD Revokes
Cluing color to a [PTD](#Permission-To-Discard) card means play if the card could have become playable since it was given [PTD](#Permission-To-Discard). Otherwise, it revokes the [PTD](#Permission-To-Discard) and calls the leftmost unclued card to play.

---

### Number Clues
This section covers giving number clues to previously unclued cards.

#### Trash Push
When all of the cards of a particular number are trash, clues using that number are treated like [Color Pushes](#Color-Pushes).

#### Negative Number Tempo Clues
Any number clue to a new card which reveals an already clued card as playable via [Empathy](#Empathy) + [Good Touch Principle](#Good-Touch-Principle) has no additional meaning.

---

### Free Choice
This section covers situations where a player has multiple known [Safe Actions](#Safe-Actions) to choose between.

#### Shout Discard
If you have both a known play and a known discard, choosing to discard causes a [Chop Move](#Chop-Move).

*Notable Exception* - If your only playable card just became playable by [Good Touch](#Good-Touch) due to your partner's blind-play, you are allowed to take a signaled discard without triggering this convention. This gives your partner an opportunity to fix a card that they couldn't predict was going to bomb.

#### Play Order
Players may freely choose between cards with different [Empathy](#Empathy) without conveying information. However, players are expected to play cards with identical [Empathy](#Empathy) in "[Focus](#Focus) first, then 15432" order, unless they are **1**'s, in which case [1's Play Order](#1's-Play-Order) applies instead.

#### 1's Play Order
As an exception to [Play Order](#Play-Order), players are expected to play clued **1**'s with identical **Empathy** in "[Chop](#Chop) first, then left-to-right" order.

Note: [Chop](#Chop) only comes first if the **1**'s clue is given to an [Unloaded](#Loaded) player.

#### Trash Order
Players are expected to discard [Empathy](#Empathy) trash first, clued cards which are conventionally trash second, and [PTD](#Permission-To-Discard) last. Within the two trash categories, players are expected to discard right-to-left.

Note: With multiple [PTD](#Permission-To-Discard), players are allowed to discard whichever card they believe is most likely to be trash.

#### Order Chop Move
When choosing between multiple plays or multiple discards, skipping forward through the order causes a number of [Chop Moves](#Chop-Move) equal to the number of skips.

#### Excessive Chop Move PTD
When a [Free Choice](#Free-Choice) convention would indicate more [Chop Moves](#Chop-Move) than the number of unclued cards that can be [Chop Moved](#Chop-Move), it [Chop Moves](#Chop-Move) all of them, but it also gives [PTD](#Permission-To-Discard) to the previously [Chop Moved](#Chop-Move) card that is **n-th** in [Discard Precedence](#Discard-Precedence) where **n** is the number of excess [Chop Moves](#Chop-Move). See the [Unlocked Starting Hands](#Unlocked-Starting-Hands) convention for details on how these two conventions interact.

For example, suppose Alice has `y5 b5 [g4] [g2] (r4)` (`g4` and `g2` are [Chop Moved](#Chop-Move) and `r4` is clued), and Bob takes an action which indicates four [Chop Moves](#Chop-Move). Alice will [Chop Move](#Chop-Move) both `y5` and `b5` and mark [PTD](#Permission-To-Discard) on the `g4`.

#### Privately-known Actions
When a player knows about a safe action that has not been conventionally promised, demonstrating this private knowledge generally doesn't trigger [Free Choice](#Free-Choice) conventions. Notably, it can still trigger [Unlock Promise](#Unlock-Promise) and [Zero Clue Safety Promise](#Zero-Clue-Safety-Promise).

---

### Early Game
This section covers conventions that uniquely apply near the beginning of the game.

#### Strong 1's Promise
If a player has multiple **1**'s in their [Starting Hand](#Starting-Hand) and all of them are good, it is expected that they will receive a **1** clue instead of a [Color Push](#Color-Pushes). When a player later finds out that they held starting hand **1**'s that were not clued this way, they should assume at least one of them is [Trash](#Trash).

#### No Stalls on the first turn
We pretend that the first turn of the game is not an eight clue turn, and therefore no [Eight Clue](#Eight-Clues) conventions apply.

Note: This means that [Unloaded Chop Move Principle](#Unloaded-Chop-Move) applies even though you are forced to clue.

#### Unlocked Starting Hands
There is an assumption that each player's starting hand cannot be [Locked](#Locked). This means that a [Number Discard](#Number-Discards) targeting [Chop](#Chop) on the first turn of the game just means to discard [Chop](#Chop) instead of indicating a [Lock](#Locked). It also affects the [Excessive Chop Move PTD](#Excessive-Chop-Move-PTD) convention. Namely, it takes one less [Chop Move](#Chop-Move) to trigger the convention.

#### 4's Direct Discard Clue
Cluing **4** to a starting hand is not usually a [Number Discard](#Number-Discards). Instead it just means to discard the **4** that was hardest to target with a [Number Discard](#Number-Discards). However, if none of the **4**'s could've possibly been difficult to target, then the clue should be interpreted as a regular [Number Discard](#Number-Discards) after all.

---

### Miscellaneous

#### Good Touch Play Policy
- If a clued card is globally known to be either [Trash](#Trash) or [Immediately Playable](#Playable), then it should be played.
- If adding one additional assumption -- that there are no same-hand duplicates -- to the *globally known information* would result in a card fitting the above bullet point, then it should also be played. (e.g. `y3` is played and you hold two yellow cards, one of which has [Negative](#Empathy) **4**.)

Note: As described in the [Shout Discard](#Shout-Discard) section, you can give your partner a turn to [Fix](#Fix) if their blind-play suddenly creates one of the above situations.

#### Gentleman's Discard
Discarding an immediately playable card promises that card in partner's hand: either among the cards that are already queued to play, or in the rightmost possible position.

Note: [Unloaded Chop Move Principle](#Unloaded-Chop-Move) does not apply to **Gentleman's Discards**.

#### Cross-hand Duplication
It is generally assumed that cross-hand duplicated 2's are treated as trash, while 3's and 4's are not. Players are allowed but not required to discard duplicated 3's and 4's.

#### Number Play PTD Inference
If a [Number Play](#Number-Plays) only touches the leftmost previously unclued card, then it was always possible to give a [Color Push](#Color-Pushes) instead. Therefore, such clues gives [PTD](#Permission-To-Discard) to the second leftmost previously unclued card.

---

### Loaded
This section covers clues given to a player who already knows about a safe action.


#### Right-Referential Number Plays
Number clues to [Loaded](#Loaded) players are right-referential play clues by default; that is, they indicate a play on the previously-unclued card to the right of the newly clued card. If there are multiple such candidates, play the rightmost candidate.

Notes:
- Similarly to [Color Pushes](#Color-Pushes), a newly clued card can be a candidate. In this case, this happens when the clue touches the two rightmost unclued cards, or when you have only one previously unclued card.
- As a special exception, the clue that would tell slot 1 to play tells it to discard instead and [Chop Moves](#Chop-Move) the rest of the cards.
- If the target cannot possibly be playable, [Loaded Direct Number Plays](#Loaded-Direct-Number-Plays) applies instead.

#### Loaded Direct Number Plays
When the target of a [Right-Referential Number Play](#Right-Referential-Number-Plays) cannot possibly be playable, but at least one of the newly clued cards can, it should be interpreted as a direct play signal on the rightmost newly clued card instead.
  
#### Loaded Fill-in Bluffs
You cannot give a [Fill-in Sacrifice](#Fill-in-Sacrifice) to a [Loaded](#Loaded) player, so any fill-in [Reclue](#Reclue) to a [Loaded](#Loaded) player calls for a blind-play of the leftmost unclued card.

Note: Cards told to play this way are [Immediately Playable](#Playable).

#### Skipping over PTD
Cards with [PTD](#Permission-To-Discard) are treated as clued per [CCC](#Called-Cards-are-Clued) and are therefore skipped over by [Color Pushes](#Color-Pushes) and also cannot be the target of [Right-Referential Number Plays](#Right-Referential-Number-Plays). See [Direct PTD Revokes](#Direct-PTD-Revokes) for clues that touch a [PTD](#Permission-To-Discard) card.

---

### Zero Clues
This section covers situations where the team has zero clue tokens.

#### Sacrifice Shout
At zero clues, choosing to discard a clued or [Chop Moved](#Chop-Move) card instead of a known safe discard or known play causes a [Chop Move](#Chop-Move). 

#### Declined Shout PTD
At zero clues, if you have the opportunity to perform a [Shout Discard](#Shout-Discard) or a [Sacrifice Shout](#Sacrifice-Shout) using a known [Non-critical](#Critical) card, declining to do so gives [PTD](#Permission-To-Discard) to your partner's [Chop](#Chop).

#### Zero Clue Safety Promise
When you choose to spend the last clue token, you should have a plan for how to exit zero clues safely. This requires that one player discards or plays a 5 to gain a clue token while their partner has a known [Safe Action](#Safe-Action).

If exiting zero clues safely might require your partner to perform a [Shout Discard](#Shout-Discard), then your clue promises that they hold a [Non-critical](#Critical) card. If your partner has a new [Chop](#Chop) (after [Unloaded Chop Move Principle](#Unloaded-Chop-Move) is applied), it is given immediate [PTD](#Permission-To-Discard). Otherwise, your partner is given permission to sacrifice their clued or [Chop Moved](#Chop-Move) card that is least likely to be critical.

---

### Locked Hand
This section covers situations where one player is signaled that they have no [Safe Actions](#Safe-Actions).

#### Locked UCM Exception
[Unloaded Chop Move](#Unloaded-Chop-Move) does not apply to any clues given by a [Locked](#Locked) player.

#### Bomb Lock
Intentionally playing known [Trash](#Trash) or a card with [PTD](#Permission-To-Discard) when your partner is [Unloaded](#Loaded) communicates that they are [Locked](#Locked).

#### Unlock Promise
When your partner is [Locked](#Locked), if you play a card that might unlock them while you have an alternative [Safe Action](#Safe-Action) that definitely doesn't, you promise that the [Connection](#Connecting-Cards) is in the rightmost possible position in their hand.

Certain actions never **Unlock Promise**: 
    - Discarding a card.
    - Playing a 5.
    - Playing an unknown card.
    - Playing a card whose [Connection](#Connecting-Cards) is known to be in your own hand.
    - Playing a card whose [Connection](#Connector-Cards) is guaranteed not to be in your partner's hand.

Other actions are candidates to unlock promise; however, for the convention to work, the unlocked player must always have at least one available action that does not **Unlock Promise**. Therefore, when all actions are potential candidates, the card that became known [Playable](#Playable) earliest is treated as though it were not a candidate. 
        
Players are expected to **Unlock Promise** their partner ASAP. Therefore, both players are expected to write notes based on declined opportunities to **Unlock Promise**. For example, if a player could have **Unlock Promised** by playing `y3` but chose not to, both players should mark the card that would have been **Unlock Promised** as `!y4`. Future **Unlock Promise** opportunities with `y3` will therefore signal information to another card.

#### Locked Color Clues
When you are [Locked](#Locked), there are two ways to get your partner's leftmost unclued card to play:
- Cluing color to your partner's second leftmost unclued card as a normal [Color Push](#Color-Pushes). Choosing this option denies your partner [PTD](#Permission-To-Discard).
- Cluing color to your partner's leftmost unclued card _without_ touching their second leftmost. Choosing this option explicitly gives [PTD](#Permission-To-Discard) to the second leftmost unclued card.

Other color clues are considered [Stalls](#Stalls).

#### Locked Number Discards
When you are [Locked](#Locked), [Right-Referential Number Plays](#Right-Referential-Number-Plays) are turned off. Instead, number clues to previously unclued cards are interpreted as [Number Discards](#Number-Discards), with three exceptions:
- You cannot [Lock](#Locked) your partner, so signaling a [Chop](#Chop) discard is allowed.
- If your partner is [Loaded](#Loaded), any number clue which touches their leftmost unclued card denies them [PTD](#Permission-To-Discard).
- If your partner already knows about a safe discard, the clue is purely a [Stall](#Stall) and gives no additional [PTD](#Permission-To-Discard).

#### Locked Hand Stalls
When you are [Locked](#Locked), a reclue that only touches cards that are [Critical](#Critical), a **2**, or already known to be [Non-critical](#Critical) should be interpreted as a [Stall](#Stalls), and therefore has no meaning beyond giving [PTD](#Permission-To-Discard) to [Chop](#Chop). However, a [Reclue](#Reclue) that reveals a card as [Non-critical](#Critical) should be interpreted as a normal [Fill-in Sacrifice](#Fill-in-Sacrifice).

Note: Declining to fill in a card while [Stalling](#Stall) can prove that it is [Non-critical](#Critical) and/or not a **2** for future [Stalls](#Stalls).

#### Lock Transfer
When you are [Locked](#Locked), discarding a useful non-duplicated card from your hand after having already given at least one [Stall](#Stalls) clue communicates that your partner is [Locked](#Locked) and should [Chop Move](#Chop-Move) their whole hand.

---

### Eight Clues

#### Eight Clue UCM Exception
[Unloaded Chop Move](#Unloaded-Chop-Move) does not apply to any clues given while the team is at eight clues.

#### Eight Clue Stalls
Reclues work identically to [Locked Hand Stalls](#Locked-Hand-Stalls).

#### Eight Clue Number Discards
These work the same as standard [Number Discards](#Number-Discards) with two exceptions:
- If your partner already knows about a safe discard, the clue is purely a [Stall](#Stall) and gives no additional [PTD](#Permission-To-Discard).
- A discard signal to [Chop](#Chop) is not a [Lock](#Locked). You may therefore need to [Bomb Lock](#Bomb-Lock) instead.

#### Discarding to eight clues
Discarding to eight clues _does_ give your partner [PTD](#Permission-To-Discard) if they are [Unloaded](#Loaded).

#### Playing at eight clues
Playing a card while at eight clues _does not_ give your partner [PTD](#Permission-To-Discard). However, if your partner is [Unloaded](#Loaded), it gives them permission to bomb their [Chop](#Chop) so that they can use the [Bomb Lock](#Bomb-Lock) convention.

#### 7-from-8 Stalls
If you are at seven clues immediately after your partner spent a clue at eight clues, and you have no cards to play, you may give a [Stall](#Stall) clue yourself as though the team were still at eight clues. This prevents situations where one player would be forced to clue repeatedly.


## Glossary

#### Playable
A card which can successfully be played. We use two different concepts of playability:
- **Immediately Playable** - can be played without waiting for anything.
- **Delayed Playable** - can be played once other known playable cards have been played first.

#### Trash
A card which can never successfully play, neither now nor in the future. This happens when a duplicate of the card has already successfully played, or when the card is unreachable due to the contents of the discard pile.

#### Critical
When there is only one remaining copy of a [Non-trash](#Trash) card, it is said to be **Critical**. 

#### Safe Action
Known [Playables](#Playable), [Trash](#Trash), and cards with [PTD](#Permission-To-Discard) are always considered **Safe Actions**.

When the team is trying to avoid blindly discarding cards as they come out of a [Zero Clue](#Zero-Clues) state, cards that are known [Non-critical](Critical) are also considered **Safe Actions**.

#### Empathy
Refers to the information known about a card strictly from clues that did and did not touch it. The **Empathy** from clues that did not touch the card are often called **Negative Empathy**. The term is also often used in combination with other terms: e.g. **Empathy Playable** refers to a card which is known [Playable](#Playable) without using any conventional knowledge.

#### Fix
A clue that proves a previously [Good Touched](#Good-Touch-Principle) card is actually [Trash](#Trash).

#### Reclue
A clue that only touches card that have already been touched by previous clues.

#### Connecting Cards
When one card plays into another card, we call the first card the **Connector** and the second card the **Connection**. e.g. `y3` is the **Connector** for `y4`, and `y4` is the **Connection** for `y3`.

#### Starting Hands
The cards that are dealt to you and your partner at the beginning of the game.

## Clarifications/FAQs
This section includes common questions about the system and clarifications about the interactions between conventions that are unwieldy to put in the main document.

**Coming Soon**

## Design Principles
This section includes principles that are useful for designing the conventions, but are not necessary for playing them.

#### Chop Policy
The two most played chop policies in Hanabi are discard-newest and discard-oldest.

Discard-newest has the following advantages:
1. Many cards are saved "for free" as a side effect of other useful clues (most notably play clues).
1. The card most likely to be trash during the early phases of the game is the card most recently drawn. To see why this is, imagine you are told to play a freshly-drawn `g1`. There are now two other copies of `g1` that have just become trash. Are they more likely to be among the cards that were already in your hand, or are they more likely to still be in the deck?

Discard-oldest has the following advantages:
1. Future discards are more predictable, which allows the team to spend clues more aggressively in decks where they can see future trash discards coming.
1. As games continue, the ratio of remaining trash cards to remaining useful unplayable cards generally increases. At some point, the ratio is large enough that the most recently drawn card is no longer particularly likely to be trash.

We have tried to create a new chop policy that combines the best of both worlds. We do this by picking a policy that is fundamentally discard-oldest and then building in mechanisms to get the two advantages of discard-newest anyway:
1. [Unloaded Chop Move Principle](#Unloaded-Chop-Move) directly gives us the first advantage of discard-newest.
1. [Starting Hand Chop Moves](#Starting-Hand-Chop-Moves), combined with repeated [Unloaded Chop Moves](#Unloaded-Chop-Moves) and [Number Discards](#Number-Discards) tends to keep the chop close to slot 1 for much of the game.

#### Referential Clues
*Coming Soon.*

#### Focus & Target
*Coming Soon.*

## Explicit Non-Conventions

#### New Card Focus
Many other systems have a policy that clues are focused on newly touched cards even when they fill in previously clued cards in an immediately actionable way. The upside of such an agreement is that clues have a higher raw efficiency in terms of cards played per clue given. However, experience has shown that being able to communicate immediately actionable information without your clues getting blocked is on balance more important than raw efficiency in 2p.

#### Priority
Many other systems require players to play known cards in a specific order so that deviating communicates something specific. We think most formulations of this convention are far too restrictive and too frequently force players to play suboptimal cards.

However, we do play a very restricted form of this convention in [Locked Hand](#Locked) situations, i.e. [Unlock Promise](#Unlock-Promise). It is possible other suitably narrowed versions of this convention could be added later.

#### Prompts
Many other systems have a convention where telling partner about a known [Unplayable](#Playable) card calls for the [Connector](#Connecting-Cards) to be played from among the already clued cards. We prefer to use such clues to call for potentially unrelated blind-plays because this means the convention simply comes up more frequently.

#### Stronger Good Touch
Many other systems have a [Good Touch Principle](#Good-Touch-Principle) that comes with much stronger guarantees than ours. Examples include:
- An assumption of no cross-hand duplication.
- A default play order that more frequently requires a [Fix](#Fix) to avoid bombs. For example, if `r3` is played and a player holds two red cards, many systems have a specific location from which the `r4` should play in the absence of a [Fix Clue](#Fix).

We prefer our weaker [Good Touch](#Good-Touch-Principle) policy for a few reasons:
- It is sometimes useful to duplicate cards between hands for endgame optimization. We would like players to be able to do this when they judge it to be correct.
- We like the flexibility of not having to fix immediately as often, which improves our ability to leverage [Unloaded Chop Moves](#Unloaded-Chop-Move) with our [Fix Clues](#Fix).


## Possible Future Conventions/Features
This section covers ideas that have not been incorporated into the system yet. 

### Idea List
- Unlock Promise Bluff
- OCM as a fix
- Javascript that adds Turbo features! (starting hand CMs and hotkey PTD notes)
- 1's reclue as a fix
- Additional ways to revoke PTD w/ Number
- Unlock Promise Discard
- Some Free Choice Conventions causing leftmost blind-play (not Priority)
- Restrict Lock Transfer (to not apply if you enter via a sac clue, not apply if conditions get "bad enough", etc.)
- Limited form of Priority
- Rank instead of Color is sometimes a stall with only one unclued card.
- Refusing to give a Safe Action when you could just gives more Safe Actions!


#### Locked Color Clues (Proposal)
We use the following priority for interpreting color clues (locked hand):
    
1. Filling in a card as playable or trash has no further meaning (or do play fill-ins give ptd to the chop? does loadedness matter?).
1. Cluing color to slot "1" is a direct play, giving ptd on slot "2" (or to chop?) if it is unclued. 
1. Filling in the color of a queued unknown playable gives ptd to the chop. 
1. Cluing color to the slot "2" (or to the chop?) is a play signal of slot 1.
1. An appropriate fill-in reclue can be a sacrifice. 
1. Other clues are stalls and give the chop ptd. 
    
None of these color clues chop move, however they may save the chop if they touch it.
