There are two major equivalent ways to think about Turbo. The first is that it's what happens if we start with Referential Sieve and then strengthen the Sieve Principle, demanding that no drawn cards can ever bypass the sieve for free. The second is that this is just a discard oldest system with a plethora of non-permanent chop moves (most cards in the starting hand and then some).
sjdrodge - Sieve Principle via Sieve Conventions and Strong Sieve Principle via this system
pianoblook & piper - Referential Principle via the Good Trash System
timotree - putting Sieve Principle and Referential Principle together to make Referential Sieve
Libster - helping with Strong Sieve Principle
Floriman - the idea that discard oldest + starting hand chop moves might be a strong alternative to sieve systems
Conventions in this section are assumed to be on; they have a proven track record.
The card on chop has the highest discard precedence. Precedence then descends through the unclued cards to the left and wraps around through the unclued "chop moved" cards.
Rank clues give a discard instruction to the unclued card to their left. If you give a discard instruction to the card with highest discard precedence (chop), it locks that player instead. If multiple cards are referred to, the discard instruction applies to the off-chop card with highest discard precedence.
Color clues newly-touching a card gives a play instruction to the card it mirrors to through the previously-untouched cards. When multiple cards are mirrored to, the target is the one leftmost in hand that is potentially playable.
If all unaccounted-for cards of a given rank are playable, a clue of that rank is a direct play clue instead of discard clue.
Any clue which fills in a previously clued card and turns it into a safe action (trash or playable) is not a referential clue.
Chop begins on slot 1 (all other starting hand cards are "chop moved").
These conventions aren't necessary to play Turbo, but they are nice to have.
We say slot 1 is to the right of slot 5, and slot 5 is to the left of slot 1.
The order for direct rank playable cards to be played is as follows:
1s follow the direct rank play clues ordering. If Alice plays her 1s out of order, she is shifting Bob's discard to the left (with wrapparound) by that many cards. If there aren't enough untouched cards, then Bob is locked.
On the first turn for each player, a rank clue touching slot 2 is a starting hand stall. The clue reciever should give a clue back. If they give a clue back touching slot 2, it is also a starting hand stall.
If a starting hand stall is given on turn 2 when the clue giver was not required to stall, and no followup clue is given on turn 4, then the turn 2 starting hand stall acts as a referential discard clue.
When Alice gives a play clue to enter a 0 clue state, she usually promises a safe discard in Bob's hand. The card is the rightmost untouched not-cm'd card in Bob's hand. When this card exists, the situation is generally safe. When the card does not exist, the situation is generally unsafe.
In a safe 0-clue state, when Alice's (future) chop is not known to be a safe discard, Bob is expected to scream discard for it. Not discarding immediately promises Alice a safe discard if she does not already have one.
When Bob is not promised a safe discard and Alice only has one discard, the situation is unsafe. Players should be scared. There should be an agreement on what card will discard if players are unable to play into each other, and that discard can occur early if a player sees that the one in their teammate's hand is bad. Generally, unsafe situations will resolve by either
Conventions in this section are being tested. There's no guarantee that they are mutually consistent.
An unbalanced state is one where one player has significantly more safe actions than the other. The main way this can occur is when a player without any safe actions is able to give highly efficint clues to their teammate (no-infos, trash pushes). While ascending the hump, without special conventions to handle them, unbalanced states can feel bad to enter. It can be impossible to save cards entering the more loaded player's hand, and it can be more expensive to lock the less loaded player's hand. This higher lock expense incentivises the less-loaded player to give underinformative clues. This section exists to mitigate that.
Suppose Bob is loaded with (future) chop currently on or rightward of slot 2. Then Alice's rank clues touching cards left of (and including) chop are early save clues, referring leftward and biased on the rightmost in the sieve queue. Not saving all cards in the discard queue can provide Bob with a safe discard (early permission to discard). With permission to discard, Bob can lock Alice more easily.
If Alice has a play and a discard, she can chop move one card in Bob's hand by taking the discard. When playing with discards being expected from the right, discarding a leftward known discardable could chop-move multiple cards (is this h-group?).
A player's starting hand is chop-moved after they take/receive their first action. Then, ptd will be given to the rightmost card, starting hand stalls touch the leftmost card in hand, and starting hand discard signals refer left with a right-bias. OCMs will index in from the right.
This, in my (sodium's) opinion, is a simpler agreement than cm'ing all but the leftmost; in the alternative, OCMs (discards wrapparound to the rightmost?) and starting hand stalls (apparent discard clue touching slot 2?) in particular are less intuitive in such a situation.
For the first 2 (4? 6?) turns of the game, swap clue meanings: rank clues are referential plays, color clues are referential discards / starting hand stalls.
If a 4 is touched and is (global/empathy) known to be noncritical 2+ away from playable, discarding it (the leftmost of these) is the chop action. Taking this discard for free can lead to
Because this convention is based in a claim about the use of these good cards, this chop is harder to cm: a card would have to play/discard that makes at least one possible (global) identity of the 4 2-away or critical.
At sufficiently low clue states, revoking permission to discard better have a good reason: it should either be a double discard situation or it should promise a safe way out.
When Alice gives a play clue to enter a 0 clue state, she usually promises a safe discard in Bob's hand. The card is the rightmost untouched not-cm'd card in Bob's hand. When this card exists, the situation is generally safe. When the card does not exist, the situation is generally unsafe.
In a safe 0-clue state, when Alice's (future) chop is not known to be a safe discard, Bob is expected to scream discard for it. Not discarding immediately promises Alice a safe discard if she does not already have one.
When Bob is not promised a safe discard and Alice only has one discard, the situation is unsafe. Players should be scared. There should be an agreement on what card will discard if players are unable to play into each other, and that discard can occur early if a player sees that the one in their teammate's hand is bad. Generally, unsafe situations will resolve by either