Kifu
A kifu (棋譜) is a game record. Each settled ranked game can be minted once as a Kifu, an ERC-721 owned by the game's winner. Its whole record lives onchain, and its artwork, SGF and metadata are built from that record whenever they're read. The contract is OpenZeppelin's ERC-721 component in a Dojo contract.
A real kifu, read back from the contract's svg view: the final
position with each stone's move number, the result, the players and the
date.
Minting
mint(game_id, anchor, record)
Anyone may send it, so it can ride in the same multicall as the settlement. The token goes to the winner regardless of who sends it, and the token id is the game id. A mint succeeds only if:
- the game is settled;
- it's a ranked game, opened from a matchmaker's ticket (not merely timed);
- it has a winner: a drawn game has no kifu;
- it hasn't been minted before.
Verification
The record is checked against what the channel settled:
- the anchor must hash to the channel's settled state hash;
- the final position the record unpacks to must equal the anchor's board;
- the steps' transcript, recomputed from the record, must equal the anchor's transcript hash.
The encoding is canonical: decoding rejects anything the encoder wouldn't produce, so each game has exactly one record that mints.
The SDK's kifuRecord(session) packs a finished game, and mintKifuCall
builds the call.
The record
The Kifu model stores only the packed steps and final position:
- Steps. Each step is one digit in base
size² + 8: a point is its own code, and the eight codes after the points are Pass, Accept, Resume, Propose, Resign (by either seat), and the referee's Flag and Start. - Dead stones. A proposal's dead stones follow its code in whichever form is shorter: a count and gaps for a few stones, a bitmap for many.
- Final position. One bit per point ever played says whether it holds a stone at the end, which gives the final position without replaying captures.
- No step count. It's the settled anchor's sequence number.
Digits pack into felts in two lanes (the low 128 bits, then 123 above them),
so every digit is u128 arithmetic and decoding is cheap enough for views.
Recorded games take 3 felts on 9×9, 7 on 13×13 and 12–14 on 19×19; a
529-step stress game takes 20.
Reading a kifu
| View | Returns |
|---|---|
summary(token_id) | Players, winner, loser, board, komi, moves, how the game ended, scores, captures and date. |
svg(token_id) | The final position with each stone's move number, dead stones, territory and the result. |
sgf(token_id) | The game as SGF, for any Go program. |
token_uri(token_id) | ERC-721 metadata as a data:application/json, URI, with the SVG inside it and traits for result, winner, how it was won and board. |
Everything is rendered on read from the stored record, so nothing is stored twice.
Minting also emits a KifuSummary event with the same fields as
summary, which Torii indexes for queries across kifus.
Dating
A kifu is dated by its game's settlement: the channel records the block timestamp of the transaction that settled the game, so minting later changes nothing.