CGSN Examples

Practical scenarios illustrating Chess Game Status Notation v1.0.0 core concepts.

Overview

This document demonstrates CGSN’s key principles through focused examples:

Inferable vs. Explicit-only: Which statuses can be derived from position
Rule-agnostic interpretation: How status remains independent of competitive outcomes
Integration patterns: Usage within PCN

Inferable Statuses

Statuses that can be determined from position analysis when game rules are known.

`checkmate`

Scholar’s Mate position:

{
  "setup": "r1bqkb1r/pppp1ppp/2n2n2/4p2Q/2B1P3/8/PPPP1PPP/RNB1K1NR / c/C",
  "moves": [
    ["e2", "e4"], ["e7", "e5"],
    ["f1", "c4"], ["b8", "c6"],
    ["d1", "h5"], ["g8", "f6"],
    ["h5", "f7"]
  ],
  "status": "checkmate"
}

Observable: Black king on e8 is attacked by white queen on f7, no legal moves available.

Rule-agnostic interpretation:

Traditional chess: White wins
Suicide chess: White loses (opponent forced to capture)
CGSN records: “Terminal piece in checkmate position”

`stalemate`

Stalemate position:

{
  "setup": "7k/5Q2/6K1/8/8/8/8/8 / c/C",
  "moves": [],
  "status": "stalemate"
}

Observable: Black king on h8 has no legal moves but is not in check.

Rule-agnostic interpretation:

Western chess: Draw
Some variants: Loss for stalemated player
CGSN records: “No legal moves, terminal piece not in check”

`insufficient`

Bare kings position:

{
  "setup": "4k3/8/8/8/8/8/8/4K3 / C/c",
  "moves": [],
  "status": "insufficient"
}

Observable: Only kings remain. Under Western chess rules, checkmate is impossible.

Rule-agnostic interpretation:

Western chess: Draw
Variants with different rules: May continue
CGSN records: “Insufficient material for checkmate”

Explicit-Only Statuses

Statuses requiring information external to position — must be explicitly recorded.

`resignation`

Mid-game position with resignation:

{
  "setup": "rnsmksnr/8/pppppppp/8/8/PPPPPPPP/8/RNSKMSNR / M/m",
  "moves": [],
  "status": "resignation"
}

Why explicit-only: Position is playable. Nothing indicates resignation occurred.

Rule-agnostic interpretation:

Traditional: Resigning player loses
CGSN records: “A player resigned” (not which player)

Note: This example uses Makruk starting position, demonstrating that resignation can occur in any game tradition, even before the first move.

`time_limit`

Active position with time exceeded:

{
  "setup": "+rnbq+kbn+r/+p+p+p+p+p+p+p+p/8/8/4P3/8/+P+P+P+P1+P+P+P/+RNBQ+KBN+R / c/C",
  "moves": [
    ["e2", "e4"]
  ],
  "status": "time_limit"
}

Why explicit-only: Time information not encoded in position.

Rule-agnostic interpretation:

Blitz: Player loses
Correspondence: May be adjudicated
CGSN records: “Time limit was exceeded”

`repetition`

Position with threefold repetition:

{
  "setup": "+r1bq+kbn+r/+p+p+p+p1+p+p+p/2n5/8/8/2N5/+P+P+P+P1+P+P+P/+R1BQ+KBN+R / C/c",
  "moves": [
    ["b1", "c3"], ["b8", "c6"],
    ["c3", "b1"], ["c6", "b8"],
    ["b1", "c3"], ["b8", "c6"],
    ["c3", "b1"], ["c6", "b8"]
  ],
  "status": "repetition"
}

Why explicit-only: Requires complete move history to detect repetition.

Rule-agnostic interpretation:

Western chess: Draw claimable
Xiangqi: Different repetition rules
CGSN records: “Position repetition occurred”

Integration with PCN

Status Explicitly Declared

{
  "sides": {
    "first": { "style": "CHESS" },
    "second": { "style": "chess" }
  },
  "setup": "+rnbq+kbn+r/+p+p+p+p+p+p+p+p/8/8/4P3/8/+P+P+P+P1+P+P+P/+RNBQ+KBN+R / c/C",
  "moves": [
    ["e7", "e5"]
  ],
  "status": "resignation"
}

PCN explicitly declares resignation (explicit-only status, cannot be inferred).

Status Omitted (Inferable)

{
  "sides": {
    "first": { "style": "CHESS" },
    "second": { "style": "chess" }
  },
  "setup": "r1bqkb1r/pppp1ppp/2n2n2/4p2Q/2B1P3/8/PPPP1PPP/RNB1K1NR / c/C",
  "moves": [
    ["e2", "e4"], ["e7", "e5"],
    ["f1", "c4"], ["b8", "c6"],
    ["d1", "h5"], ["g8", "f6"],
    ["h5", "f7"]
  ]
}

PCN omits status. Implementation can infer checkmate from position.

Status Declared for Clarity

{
  "setup": "4k3/8/8/8/8/8/8/4K3 / C/c",
  "moves": [],
  "status": "insufficient"
}

Even though insufficient is inferable, explicit declaration removes ambiguity.

Cross-Game Applicability

Western Chess

{
  "setup": "r1bqkb1r/pppp1ppp/2n2n2/4p2Q/2B1P3/8/PPPP1PPP/RNB1K1NR / c/C",
  "status": "checkmate"
}

Japanese Shōgi

{
  "setup": "ln1gk1snl/1r5b1/p1ppppppp/9/1p7/2P6/PP1PPPPPP/1B5R1/LNSGKGSNL P/p s/S",
  "status": "checkmate"
}

Chinese Xiangqi

{
  "setup": "3a1k3/9/9/9/9/9/9/9/4R4/3AK4 / X/x",
  "status": "checkmate"
}

Same CGSN status (checkmate) applies across different game traditions, demonstrating rule-agnostic universality.

Summary

Key Principles

Inferable statuses (checkmate, stalemate, insufficient) can be omitted—position provides information
Explicit-only statuses (resignation, time_limit, repetition) must be recorded—cannot be derived
Rule-agnostic design: Same status, different competitive interpretations
Integration flexibility: Works seamlessly with PCN and other formats

Usage Guidelines

Always explicitly record:

resignation, time_limit, move_limit, agreement, illegal_move, repetition

Can omit when position is clear:

checkmate, stalemate, bare_king, mare_king, insufficient, in_progress

Validate appropriately:

Verify status string format
Check against defined CGSN values
Optionally validate status-position consistency for inferable statuses