Hanabi Convention Lab

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Hints
Lives
Deck

Click a player badge to move the acting seat. C1 is leftmost from the card owner's view.

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You will see every hand except your own, just like at a Hanabi table.

Help & conventions

A convention adds an agreed message to a legal color or number hint. Players still cannot see their own cards.

Simple Recommendation

3, 4, or 5 players

  1. The hint giver assigns a recommendation number to each other player's hand using that hand and the public board.
  2. Add those numbers and take the remainder modulo 8, 12, or 16 for 3, 4, or 5 players. This selects a hint channel: a prescribed target and color/number hint. If that exact hint is unavailable, the bot skips it.
  3. Each other player subtracts the recommendation numbers of the visible peers to recover their own. The action algorithm decides when to follow it or give a more useful hint.

Three-player arithmetic: channel 5 − visible peer's 3 = your 2 (modulo 8). Recommendation 2 means play C2, if the freshness rule permits.

Dynamic Recommendation

3 players

Also uses modulo-8 encoding, but the decoded message updates a shared convention state rather than one stored action. Hint channels use which old, middle, or new positions are touched.

Each hand tracks unknown / playable / unplayable marks, known 5s, and a chop. These marks move with the cards; a successful play can make previously unplayable cards worth reconsidering.

In ordinary turns, the bot checks whether the next player needs protection before playing a marked playable card, then weighs a hint against discarding. The final-round policy changes when the deck is empty.

Simple recommendation numbers
PlayersPlayDiscard / protectNo new action
3 · mod 81–5 → C1–C50 → discard chop; 6 → keep chop and discard the first legal non-chop position7
4 · mod 121–4 → C1–C45–8 → discard C1–C40, 9–11
5 · mod 161–4 → C1–C45–8 → useless C1–C4; 9–12 → dispensable C1–C40, 13–15

The number recommends an action; legality, freshness, and higher-priority hint rules still apply.

Physical hint-channel lookup

Seat offsets follow turn order and wrap around: +1 is the next player. A hint always touches every card of the chosen color or number, not just the card used to choose it.

Simple Recommendation

Left means use C1's number or color. Right means scan from the newest card back toward C1 and use the first number or color different from C1's. If none differs, that right channel is unavailable.

Hint choice3 players: +1 / +24 players: +1 / +2 / +35 players: +1 / +2 / +3 / +4
Left number0 / 10 / 1 / 20 / 1 / 2 / 3
Left color2 / 33 / 4 / 54 / 5 / 6 / 7
Right number4 / 56 / 7 / 88 / 9 / 10 / 11
Right color6 / 79 / 10 / 1112 / 13 / 14 / 15

Dynamic Recommendation · 3 players

NEW touches the newest card (even if C1 is also touched). OLD touches C1 but not the newest card. MID touches neither end. For channels 0–3, the bot prefers OLD and uses MID only when OLD is unavailable. A full-hand hint is an abandon-convention signal, not an encoded channel.

Hint shape and typeNext player (+1)Previous player (+2)
OLD / MID number01
OLD / MID color23
NEW number45
NEW color67

NEW uses the newest card's attribute. MID uses the lowest rank, or first color in W/R/Y/G/B order, whose matches are all in middle positions. Dynamic also verifies that the physical hint matches the convention's chosen hint; an arbitrary literal hint need not encode a message. The channel number is the combined sum, not your decoded instruction: subtract the other visible receiver's recommendation modulo 8.

Words on the board

C1, C2, …
Positions in the card owner's hand order, oldest to newest. Read the C-labels even when the hand wraps into two rows.
Acting seat
The player whose decision is being evaluated. Click a player badge to change it in Position lab.
Hint giver / recipient / receiver
The giver sends the hint; the recipient's cards are touched. Every non-giver can be a receiver who decodes a recommendation, not just the recipient.
Hint channel
The agreed meaning of a hint's target, type, and touched positions. Its number encodes the combined message, not one player's action.
Stored recommendation · Rec
A Simple player's latest decoded instruction. A new encoded hint replaces it; playing or discarding clears that player's instruction.
Freshness
A Simple play recommendation can be followed after zero team plays since the hint, or after exactly one if at least two lives remain.
Chop
The convention's discard position. Simple uses the newest/rightmost card as chop, distinct from its default C1 discard. Dynamic tracks a movable chop.
Playable
The next rank needed by its color's firework. A last remaining copy that is playable is still labeled playable.
Useless
Already covered by a firework, or unreachable because every copy of a required lower rank was lost. Safe to discard for scoring.
Critical
A still-needed, not-yet-playable card's last remaining copy. Losing it blocks further progress through that rank.
Dispensable
Still useful but not playable now, with another copy remaining. Discarding it costs a backup copy; it is not automatically the best move.
Seed
Reproduces the initial shuffled deck. The same strategy, seed, and choices reproduce the same game.

Card classifications describe actual cards for learning. They are not extra knowledge a player has about their own hidden hand, and differ from Dynamic's inferred playability marks.

Using the Lab

Position lab
Click a card's number or background to swap it with a real copy: deck first, then discard, then another hand. The outgoing card takes that copy's place. If the only copy is played, its firework is lowered and displaced cards return to the deck. Click the deck to order draws. Ask the bot explains the decision.
Watch / Replay
Step through generated games, or load JSON/YAML records. Replay flags moves where the current bot differs from the saved choice.
Play with bots
Click your hidden card to play/discard, or a teammate's card to hint. Each turn's animation finishes before the next appears.
Keyboard and playback
Tab through controls and use Enter or Space to choose an action. Opening card actions focuses the first choice; Cancel or Escape returns to that card. Timeline arrow keys move through turns. Stepping or scrubbing pauses autoplay so you can read the explanation. Reduced-motion preferences keep the feedback without the moving effects.
Debug / helper
Shows convention memory and readable card statuses. Your own cards stay hidden during Play. Watch and Replay let you inspect the deck. In Play, View inspects any past move without changing the game; Branch before one of your moves removes the later branch so you can choose again. Current turn returns to live play.
Saving and resuming
Open Workspace files at the bottom of the page. Save workspace downloads your position, games, and current timeline steps. Load workspace restores that file, including playable human games. Save replay downloads just one game for the Replay tab. Keep these files: closing or refreshing the page does not save automatically, and the browser warns about unsaved changes. Recordings reconstruct the game with the current strategy engine.
Deck editing
Opening the deck does not change it. Apply order commits your draft; Cancel leaves the original untouched. Restore original resets the draft to the order on entry. Shuffle creates a new draft order. Sampling a different position closes the old deck editor.