lila-tablebase

Tablebase server for lichess.org, based on shakmaty-syzygy.

Blog posts

• Op1 - Partial 8-piece tablebase available
• Optimizing the tablebase server
• 7 piece tablebases are complete

Usage

cargo run --release -- --help

HTTP API

GET /standard

curl http://tablebase.lichess.ovh/standard?fen=4k3/6KP/8/8/8/8/7p/8_w_-_-_0_1

name	type	default	description
fen	string	required	FEN of the position. Underscores allowed.

{
  "dtz": 1, // dtz50'' with rounding or null if unknown
  "precise_dtz": 1, // dtz50'' (only if guaranteed to be not rounded) or null if unknown
  "dtc": null, // depth to conversion or null if unknown
  "dtm": 17, // depth to mate or null if unknown
  "dtw": null, // depth to antichess win or null if unknown
  "checkmate": false,
  "stalemate": false,
  "variant_win": false, // only in chess variants (atomic, antichess)
  "variant_loss": false, // only in chess variants
  "insufficient_material": false,
  "category": "win", // win, unknown, syzygy-win, maybe-win, cursed-win, draw, blessed-loss, maybe-loss, syzygy-loss, loss
  "moves": [ // information about legal moves, best first
    {
      "uci": "h7h8q",
      "san": "h8=Q+",
      "dtz": -2,
      "precise_dtz": -2,
      "dtc": null,
      "dtm": -16,
      "dtw": null,
      "zeroing": true,
      "checkmate": false,
      "stalemate": false,
      "variant_win": false,
      "variant_loss": false,
      "insufficient_material": false,
      "category": "loss" // loss, unknown, syzygy-loss, maybe-loss, blessed-loss, draw, cursed-win, maybe-win, syzygy-win, win
    },
    // ...
  ]
}

GET /standard/mainline

curl http://tablebase.lichess.ovh/standard/mainline?fen=4k3/6KP/8/8/8/8/7p/8_w_-_-_0_1

name	type	default	description
fen	string	required	FEN of the position. Underscores allowed.

{
  "dtz": 1,
  "mainline": [ // dtz mainline or empty if drawn
    { "uci": "h7h8q", "san": "h8=Q+", "dtz": -2 },
    { "uci": "e8d7", "san": "Kd7", "dtz": 1 },
    { "uci": "h8h2", "san": "Qxh2", "dtz": -14 },
    { "uci": "d7c6", "san": "Kc6", "dtz": 13 },
    { "uci": "h2e5", "san": "Qe5", "dtz": -12 },
    { "uci": "c6b6", "san": "Kb6", "dtz": 11 },
    { "uci": "g7f6", "san": "Kf6", "dtz": -10 },
    { "uci": "b6a6", "san": "Ka6", "dtz": 9 },
    { "uci": "e5b2", "san": "Qb2", "dtz": -8 },
    { "uci": "a6a5", "san": "Ka5", "dtz": 7 },
    { "uci": "f6e5", "san": "Ke5", "dtz": -6 },
    { "uci": "a5a4", "san": "Ka4", "dtz": 5 },
    { "uci": "e5d4", "san": "Kd4", "dtz": -4 },
    { "uci": "a4a5", "san": "Ka5", "dtz": 3 },
    { "uci": "d4c5", "san": "Kc5", "dtz": -2 },
    { "uci": "a5a4", "san": "Ka4", "dtz": 1 },
    { "uci": "b2a2", "san": "Qa2#", "dtz": -1 }
  ],
  "winner": "w" // (w) white, (b) black, (null) draw
}

Claims draw by 50-move rule as soon as possible and ends the mainline. Error 404 if not a tablebase position or required tables not present.

GET /atomic

GET /antichess

Acknowledgements

Thanks to Ronald de Man for his Syzygy endgame tables. Thanks to Bojun Guo for generating and sharing 7-piece tables.

License

lila-tablebase is licensed under the GNU Affero General Public License 3.0 (or any later version at your option). See the COPYING file for the full license text.