/start

Starts a new game.

variant

The chess variant as per these options.

• classical chess, also known as standard or slow chess.
• 960 is the same as classical chess except that the starting position of the pieces is randomized.
• dunsany is an asymmetric variant in which Black has the standard chess army and White has 32 pawns.
• losing chess, the objective of each player is to lose all of their pieces or be stalemated.
• racing-kings consists of being the first player to move their king to the eighth row.
• capablanca incorporates two new pieces, the archbishop and the chancellor, and is played on a 10×8 board.
• capablanca-fischer is a mix of Capablanca chess and Chess960.

mode

The game mode as per these options.

• analysis is used to start games for further analysis.
• play allows to play chess online with other players.
• stockfish allows to play chess against the computer.

settings (optional)

Additional optional parameters may be required depending on the mode selected as shown in the examples below.

• color
• fen
• increment
• min
• movetext
• startPos
• submode

---

Usage

Start a classical game

ws.send('/start "{\\"variant\\":\\"classical\\",\\"mode\\":\\"analysis\\"}"');

{
  "/start": {
    "variant": "classical",
    "mode": "analysis",
    "turn": "w",
    "movetext": "",
    "fen": [
      "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq -"
    ]
  }
}

Start a classical game from a FEN position

Name	Description	Required
settings	fen	Yes

ws.send('/start "{\\"variant\\":\\"classical\\",\\"mode\\":\\"analysis\\",\\"settings\\":{\\"fen\\":\\"r1bqkbnr/pppppppp/2n5/8/3PP3/8/PPP2PPP/RNBQKBNR b KQkq d3\\",\\"movetext\\":\\"\\"}}"');

{
  "/start": {
    "variant": "classical",
    "mode": "analysis",
    "turn": "b",
    "movetext": "",
    "fen": [
      "r1bqkbnr/pppppppp/2n5/8/3PP3/8/PPP2PPP/RNBQKBNR b KQkq -"
    ]
  }
}

Start a classical game from a SAN movetext

Name	Description	Required
settings	movetext	Yes

ws.send('/start "{\\"variant\\":\\"classical\\",\\"mode\\":\\"analysis\\",\\"settings\\":{\\"fen\\":\\"rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq -\\",\\"movetext\\":\\"1.e4 Nc6 2.d4\\"}}"');

{
  "/start": {
    "variant": "classical",
    "mode": "analysis",
    "turn": "b",
    "movetext": "1.e4 Nc6 2.d4",
    "fen": [
      "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq -",
      "rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3",
      "r1bqkbnr/pppppppp/2n5/8/4P3/8/PPPP1PPP/RNBQKBNR w KQkq -",
      "r1bqkbnr/pppppppp/2n5/8/3PP3/8/PPP2PPP/RNBQKBNR b KQkq d3"
    ]
  }
}

Start a Chess960 game from a SAN movetext

Name	Description	Required
settings	movetext startPos	Yes

ws.send('/start "{\"variant\":\"960\",\"mode\":\"analysis\",\"settings\":{\"fen\":\"bnrkqbrn/pppppppp/8/8/8/8/PPPPPPPP/BNRKQBRN w KQkq -\",\"movetext\":\"1.e4 Nc6 2.d4\",\"startPos\":\"RBQKBNRN\"}}"');

{
  "/start": {
    "variant": "960",
    "mode": "analysis",
    "turn": "b",
    "movetext": "1.e4 Nc6 2.d4",
    "fen": [
      "bnrkqbrn/pppppppp/8/8/8/8/PPPPPPPP/BNRKQBRN w KQkq -",
      "bnrkqbrn/pppppppp/8/8/4P3/8/PPPP1PPP/BNRKQBRN b KQkq e3",
      "b1rkqbrn/pppppppp/2n5/8/4P3/8/PPPP1PPP/BNRKQBRN w KQkq -",
      "b1rkqbrn/pppppppp/2n5/8/3PP3/8/PPP2PPP/BNRKQBRN b KQkq d3"
    ],
    "startPos": "RBQKBNRN"
  }
}

Start a classical game in Stockfish mode

Name	Description	Required
settings	color	Yes

ws.send('/start "{\\"variant\\":\\"classical\\",\\"mode\\":\\"stockfish\\",\\"settings\\":{\\"color\\":\\"b\\"}}"');

{
  "/start": {
    "variant": "classical",
    "mode": "stockfish",
    "color": "b",
    "fen": "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq -"
  }
}

Start a classical game to play online

Name	Description	Required
settings	min increment color submode	Yes

ws.send('/start "{\\"variant\\":\\"classical\\",\\"mode\\":\\"play\\",\\"settings\\":{\\"min\\":\\"5\\",\\"increment\\":\\"3\\",\\"color\\":\\"b\\",\\"submode\\":\\"online\\",\\"username\\":null}}"');

{
  "/start": {
    "uid": "f3caa3d1",
    "jwt": "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJhc3luYy5jaGVzc2xhYmxhYi5vcmciLCJpYXQiOjE3MjY1OTkxMDMsImV4cCI6MTcyNjYwMjcwMywidmFyaWFudCI6ImNsYXNzaWNhbCIsInVzZXJuYW1lIjp7InciOiJhbm9ueW1vdXMiLCJiIjoiYW5vbnltb3VzIn0sImVsbyI6eyJ3IjpudWxsLCJiIjpudWxsfSwic3VibW9kZSI6Im9ubGluZSIsImNvbG9yIjoiYiIsIm1pbiI6IjUiLCJpbmNyZW1lbnQiOiIzIiwiZmVuIjoicm5icWtibnIvcHBwcHBwcHAvOC84LzgvOC9QUFBQUFBQUC9STkJRS0JOUiB3IEtRa3EgLSIsInVpZCI6Ijc2M2Q1OGEyIn0.dMLEBGBJPsdII3KReOXYXoOZFmeQVJyku0q_mG2dZnk",
    "variant": "classical",
    "mode": "play",
    "fen": "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq -"
  }
}

Create an invite code to play a classical game

Name	Description	Required
settings	min increment color submode	Yes

ws.send('/start "{\\"variant\\":\\"classical\\",\\"mode\\":\\"play\\",\\"settings\\":{\\"min\\":\\"5\\",\\"increment\\":\\"3\\",\\"color\\":\\"w\\",\\"submode\\":\\"friend\\",\\"username\\":null}}"');

{
  "/start": {
    "uid": "fbb4a3f3",
    "jwt": "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJhc3luYy5jaGVzc2xhYmxhYi5vcmciLCJpYXQiOjE3MjY1OTkxOTYsImV4cCI6MTcyNjYwMjc5NiwidmFyaWFudCI6ImNsYXNzaWNhbCIsInVzZXJuYW1lIjp7InciOiJhbm9ueW1vdXMiLCJiIjoiYW5vbnltb3VzIn0sImVsbyI6eyJ3IjpudWxsLCJiIjpudWxsfSwic3VibW9kZSI6ImZyaWVuZCIsImNvbG9yIjoidyIsIm1pbiI6IjUiLCJpbmNyZW1lbnQiOiIzIiwiZmVuIjoicm5icWtibnIvcHBwcHBwcHAvOC84LzgvOC9QUFBQUFBQUC9STkJRS0JOUiB3IEtRa3EgLSIsInVpZCI6IjhkZjk1OGMyIn0.hWREwWcV-oq1EE_EhNrK9xFl1z8NTPxtG6FGeDkGLEE",
    "variant": "classical",
    "mode": "play",
    "fen": "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq -"
  }
}