# Chess Notation Tools

FEN validation and parsing, square maths, empty-board piece moves, material count, PGN tag parsing and time-control categories.

## How to pay

Machine-payable over x402. USDC on: Base (eip155:8453), Solana (solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp), Polygon (eip155:137), Arbitrum One (eip155:42161).
No accounts. No API keys. No signup. The paying wallet is the account.

## Machine-readable

- OpenAPI: https://chess-notation.x402tookit.com/openapi.json
- x402 manifest: https://chess-notation.x402tookit.com/.well-known/x402
- Catalog (free): https://chess-notation.x402tookit.com/catalog
- Health (free): https://chess-notation.x402tookit.com/health
- Uptime (free): https://chess-notation.x402tookit.com/uptime

## Endpoints (8)

### GET /fen-board — $0.02
Render a FEN position as an 8x8 ASCII board (White at the bottom) plus a piece-by-square list.
Params: fen: string
Example: https://chess-notation.x402tookit.com/fen-board?fen=r1bqkbnr%2Fpppp1ppp%2F2n5%2F4p3%2F4P3%2F5N2%2FPPPP1PPP%2FRNBQKB1R+w+KQkq+-+2+3

### GET /fen-parse — $0.02
Validate a chess FEN: syntax of all six fields, king and pawn counts, castling and en passant consistency, piece totals.
Params: fen: string
Example: https://chess-notation.x402tookit.com/fen-parse?fen=rnbqkbnr%2Fpppppppp%2F8%2F8%2F8%2F8%2FPPPPPPPP%2FRNBQKBNR+w+KQkq+-+0+1

### GET /material-count — $0.02
Material balance from a FEN: standard 1-3-3-5-9 point totals per side, difference and piece lists.
Params: fen: string
Example: https://chess-notation.x402tookit.com/material-count?fen=rnbqkbnr%2Fpppppppp%2F8%2F8%2F8%2F8%2FPPPPPPPP%2FRNBQKBNR+w+KQkq+-+0+1

### GET /pgn-headers — $0.02
Parse PGN tag pairs, check the Seven Tag Roster, result token and date format, and count the moves in the movetext.
Params: pgn: string
Example: https://chess-notation.x402tookit.com/pgn-headers?pgn=%5BEvent+%22Casual+game%22%5D%0A%5BSite+%22Paris+FRA%22%5D%0A%5BDate+%221858.%3F%3F.%3F%3F%22%5D%0A%5BRound+%22%3F%22%5D%0A%5BWhite+%22Paul+Morphy%22%5D%0A%5BBlack+%22Duke+Karl+%2F+Count+Isouard%22%5D%0A%5BResult+%221-0%22%5D%0A%0A1.+e4+e5+2.+Nf3+d6+3.+d4+Bg4+1-0

### GET /piece-moves — $0.02
Squares a knight, bishop, rook, queen, king or pawn reaches from a square on an empty board, with the count.
Params: piece: string, square: string, color?: string
Example: https://chess-notation.x402tookit.com/piece-moves?piece=knight&square=d4

### GET /square-distance — $0.02
Distance between two chess squares as king moves, rook moves, bishop moves and knight moves on an empty board.
Params: from: string, to: string
Example: https://chess-notation.x402tookit.com/square-distance?from=a1&to=h8

### GET /square-info — $0.02
File, rank, light or dark colour, 0-63 index, diagonals and mirror squares for a chess square like e4.
Params: square: string
Example: https://chess-notation.x402tookit.com/square-info?square=e4

### GET /time-control — $0.02
Classify a chess time control (bullet, blitz, rapid, classical) from base minutes and increment, with estimated length.
Params: baseMinutes: number, incrementSeconds?: number
Example: https://chess-notation.x402tookit.com/time-control?baseMinutes=5&incrementSeconds=3

## Terms

Chess notation arithmetic computed locally from the text given, per the FEN, PGN and standard algebraic conventions, provided as is. These tools check structure and count material: they do not generate legal moves, detect check or mate, evaluate positions or give move advice. Not an engine.