# Chess Notation Tools – Piece Moves from Square

> Chess Notation Tools – Piece Moves from Square is a paid API for AI agents from chess-notation.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-29).

Returns all squares a given chess piece can reach from a specified starting square on an empty board, along with the count of reachable squares.

## Facts

- Endpoint: GET https://chess-notation.x402tookit.com/piece-moves?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/chess-notation-tools-piece-moves-from-square-07429b7e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_WOe4R9EbpiLcsaoGFUqBt

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability chess-notation-tools-piece-moves-from-square-07429b7e
```

Example prompt: What squares can a knight reach from d4 on an empty chessboard, and how many squares is that total?

## When to prefer this

Use this endpoint when you need to programmatically determine the theoretical reach or mobility of a single chess piece from any board square on an empty board. Ideal for chess tutoring tools, puzzle generators, engine analysis helpers, or educational apps that need to explain piece movement rules. Prefer this over a full chess engine when you only need static piece mobility without considering other pieces or game state.

## Known failure modes

- Invalid piece name returns an error or empty result
- Invalid square notation (e.g. 'z9') returns an error
- Missing required query parameters (piece or square) returns a 400-level error
- Color parameter ignored for non-pawn pieces
- Network or service unavailability returns a 402 or 5xx error

## How this service works

Squares a knight, bishop, rook, queen, king or pawn reaches from a square on an empty board, with the count.

## Output

Returns a list of algebraic notation square names (e.g. ['c6','e6','f5','f3','e2','c2','b3','b5']) that the specified piece can reach from the given starting square on an empty board, plus a count of those squares, a summary string, and metadata fields including source square, timestamp, and optional disclaimer.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "piece",
      "square"
     ],
     "properties": {
      "color": {
       "type": "string",
       "description": "white (default) or black, used for pawns only"
      },
      "piece": {
       "type": "string",
       "description": "knight, bishop, rook, queen, king or pawn (or n, b, r, q, k, p)"
      },
      "square": {
       "type": "string",
       "description": "Starting square such as d4"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "from": {
       "type": [
        "null",
        "string"
       ]
      },
      "count": {
       "type": [
        "null",
        "number"
       ]
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ]
      },
      "squares": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "summary": {
       "type": [
        "null",
        "string"
       ]
      },
      "verdict": {
       "type": [
        "null",
        "string"
       ]
      },
      "degraded": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "disclaimer": {
       "type": [
        "null",
        "string"
       ]
      },
      "notChecked": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      }
     }
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/chess-notation-tools-piece-moves-from-square-07429b7e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from chess-notation.x402tookit.com](https://www.zero.xyz/host/chess-notation.x402tookit.com/llms.txt)