← The evidence ledger
Evidence row 2202113
Observed , by sync.x402_bazaar/1.
- Kind
- listing
- About
- source_record x402_bazaar:https://chess-notation.x402tookit.com/fen-parse
- Recorded
- Previous row
- None: the first of its kind about this subject
- Body SHA-256
- 3ed90d4b68443af1533b728d09e87fd4463a2fea0dd68dc83f27de1a6a5481ed
- Leaf
- 0x4549a0816e89b2ac58a5e6c041bf662dbf593f8ede54e5f2b31a1d899dd245f7
What was observed
{
"endpoints": [
[
"x402",
"https://chess-notation.x402tookit.com/fen-parse"
]
],
"name": "Chess Notation Tools",
"owner_address": "0xb531320805c5bed1d46aeadcf4f008fdf172dbda",
"raw": {
"accepts": [
{
"amount": "20000",
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"extra": {
"name": "USD Coin",
"version": "2"
},
"maxTimeoutSeconds": 300,
"network": "eip155:8453",
"payTo": "0xb531320805C5BED1D46AEaDcF4F008FDF172DBDa",
"scheme": "exact"
},
{
"amount": "20000",
"asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
"extra": {
"feePayer": "D6ZhtNQ5nT9ZnTHUbqXZsTx5MH2rPFiBBggX4hY1WePM",
"transactionVersions": [
0
]
},
"maxTimeoutSeconds": 300,
"network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
"payTo": "DUPiupXtuox38dcGoXUKer5mAydCzmaHjrbQ66qeEm8s",
"scheme": "exact"
},
{
"amount": "20000",
"asset": "0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359",
"extra": {
"name": "USD Coin",
"version": "2"
},
"maxTimeoutSeconds": 300,
"network": "eip155:137",
"payTo": "0xb531320805C5BED1D46AEaDcF4F008FDF172DBDa",
"scheme": "exact"
},
{
"amount": "20000",
"asset": "0xaf88d065e77c8cC2239327C5EDb3A432268e5831",
"extra": {
"name": "USD Coin",
"version": "2"
},
"maxTimeoutSeconds": 300,
"network": "eip155:42161",
"payTo": "0xb531320805C5BED1D46AEaDcF4F008FDF172DBDa",
"scheme": "exact"
}
],
"description": "Validate a chess FEN: syntax of all six fields, king and pawn counts, castling and en passant consistency, piece totals.",
"extensions": {
"bazaar": {
"info": {
"input": {
"method": "GET",
"queryParams": {
"fen": "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"
},
"type": "http"
},
"output": {
"example": {
"asOf": "2026-10-12T01:02:03.320Z",
"black": {
"bishops": 2,
"kings": 1,
"knights": 2,
"pawns": 8,
"queens": 1,
"rooks": 2
},
"castling": {
"blackKingside": true,
"blackQueenside": true,
"whiteKingside": true,
"whiteQueenside": true
},
"degraded": false,
"disclaimer": "Screening signal computed from the named public source. Not financial, legal or investment advice; provided as is. Verify at the source before acting.",
"enPassantSquare": null,
"fiftyMoveRuleReached": false,
"fullmoveNumber": 1,
"halfmoveClock": 0,
"notChecked": [
"whether the side not to move is in check (an illegal position)",
"whether the position is reachable by legal play",
"…2 more"
],
"pieceCount": {
"black": 16,
"white": 16
},
"problems": [],
"reasons": [],
"sideToMove": "white",
"source": "computed locally (FEN specification)",
"summary": "Well-formed White-to-move position, move 1.",
"valid": true,
"verdict": "VALID_POSITION_STRUCTURE",
"white": {
"bishops": 2,
"kings": 1,
"knights": 2,
"pawns": 8,
"queens": 1,
"rooks": 2
}
},
"type": "json"
}
},
"schema": {
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"additionalProperties": false,
"properties": {
"method": {
"enum": [
"GET"
],
"type": "string"
},
"queryParams": {
"properties": {
"fen": {
"description": "A FEN string, for example the start position rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1",
"type": "string"
}
},
"required": [
"fen"
],
"type": "object"
},
"type": {
"const": "http",
"type": "string"
}
},
"required": [
"type",
"method"
],
"type": "object"
},
"output": {
"properties": {
"example": {
"properties": {
"asOf": {
"type": [
"null",
"string"
]
},
"black": {
"properties": {
"bishops": {
"type": [
"null",
"number"
]
},
"kings": {
"type": [
"null",
"number"
]
},
"knights": {
"type": [
"null",
"number"
]
},
"pawns": {
"type": [
"null",
"number"
]
},
"queens": {
"type": [
"null",
"number"
]
},
"rooks": {
"type": [
"null",
"number"
]
}
},
"type": [
"null",
"object"
]
},
"castling": {
"properties": {
"blackKingside": {
"type": [
"boolean",
"null"
]
},
"blackQueenside": {
"type": [
"boolean",
"null"
]
},
"whiteKingside": {
"type": [
"boolean",
"null"
]
},
"whiteQueenside": {
"type": [
"boolean",
"null"
]
}
},
"type": [
"null",
"object"
]
},
"degraded": {
"type": [
"boolean",
"null"
]
},
"disclaimer": {
"type": [
"null",
"string"
]
},
"enPassantSquare": {},
"fiftyMoveRuleReached": {
"type": [
"boolean",
"null"
]
},
"fullmoveNumber": {
"type": [
"null",
"number"
]
},
"halfmoveClock": {
"type": [
"null",
"number"
]
},
"notChecked": {
"items": {
"type": "string"
},
"type": [
"array",
"null"
]
},
"pieceCount": {
"properties": {
"black": {
"type": [
"null",
"number"
]
},
"white": {
"type": [
"null",
"number"
]
}
},
"type": [
"null",
"object"
]
},
"problems": {
"type": [
"array",
"null"
]
},
"reasons": {
"type": [
"array",
"null"
]
},
"sideToMove": {
"type": [
"null",
"string"
]
},
"source": {
"type": [
"null",
"string"
]
},
"summary": {
"type": [
"null",
"string"
]
},
"valid": {
"type": [
"boolean",
"null"
]
},
"verdict": {
"type": [
"null",
"string"
]
},
"white": {
"properties": {
"bishops": {
"type": [
"null",
"number"
]
},
"kings": {
"type": [
"null",
"number"
]
},
"knights": {
"type": [
"null",
"number"
]
},
"pawns": {
"type": [
"null",
"number"
]
},
"queens": {
"type": [
"null",
"number"
]
},
"rooks": {
"type": [
"null",
"number"
]
}
},
"type": [
"null",
"object"
]
}
},
"type": "object"
},
"type": {
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}
}
},
"lastUpdated": "2026-11-01T22:41:56.034Z",
"quality": {
"l30DaysTotalCalls": 2,
"l30DaysUniquePayers": 2,
"lastCalledAt": "2026-11-01T22:41:55.779Z"
},
"resource": "https://chess-notation.x402tookit.com/fen-parse",
"serviceName": "Chess Notation Tools",
"tags": [
"chess",
"fen",
"validation",
"position"
],
"type": "http",
"x402Version": 2
},
"source": "x402_bazaar",
"summary": "Validate a chess FEN: syntax of all six fields, king and pawn counts, castling and en passant consistency, piece totals."
}What the leaf hashes
{"body":"3ed90d4b68443af1533b728d09e87fd4463a2fea0dd68dc83f27de1a6a5481ed","id":2202113,"kind":"listing","method":"sync.x402_bazaar/1","observed_us":1793646812532952,"prev":null,"subject":"x402_bazaar:https://chess-notation.x402tookit.com/fen-parse","subject_kind":"source_record"}Proof
Fold these into the leaf in order, hashing each sorted pair with keccak256, to reach the root of (444186 rows).
- 0x4549cac51ae733979870b24639274d37469a086f1533652b58b2d87895ce3a16
- 0x58a9ed991778972d20feec941448acfd9870964f953f1d280f0af824766d89d3
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- 0x6732ada9e7b272e33fb47ffe206c13a071bf4b2c737155dc9580821bcd6ce649
- 0xfcf692d4b595fcfb0857ca0fe71ba156c85fca24e133638b1b7510b296f7f9bc
- 0xc71c68c7e34c802a46c014ba0047ea84bbd19e4bd2551d4af53e54b3f4cd0a64
- 0x06c7db349f6a291d403e926610f38fa59ae39f53a2d14aa418653dda5c900592
- 0xc907bcfb7ccd45a65641dec8c1cc22774fe67569c69e9fab7078f8ecd5198a4c
- 0x3934b4ca9c06a3b133b972a2011dd2469d8df3335f5e14a92dfa799e39c20e6f
- 0x6ee3eb8898eb76f8d194db3cae3ddde79beb40bc4d8d7b5c3a8de2f0f9d6d1ca
- 0x9040b371d5950f0b54a05e134d8f1bf0ff2907815c22cb8410a554cb7410197b
- 0xbc7027b08c105107379103e4bb6da46cb151f2ad9354e23245ef7a2991eacef7
- 0x95a273bb8932dab7d9961e32e3d3be866bd51e98c7772b268db2595e5869b5c4
- 0x75634d9d67fe6c75f98d15ecdced550aaaa0b303b51c1355fcc39f82416bc504
- 0x3217f821997a6d778dcf0814a25b1296c55ab77710c675e7b15695d25a6ce67d
- 0x8760c227928c5295506cd8606e763f86cf8cd2a549820fab4dc86d29ca0d816d
- 0xa20b9be86af7d690e040c9060a373b2fc5498edf3432f43c26f74fa2febc1e9a
- 0x050f2978b537f7afb21ee1551577cdf146d1c56f4df12d24315ae5e69366b0a4
- 0x365b161a4b68d750dcc4b3ecce1154a2163c87b08762079428e68f0ebb6a754e
- Day root
- 0x78fecaabbe319e56f5c4b80fc02e2052e198ad24781da8832a475ff65f2002d1
- Chained
- 0xdc35957db5d1371ca382b9152878ffece28ec7c5cb4f98fd71ddb367f8b999b2
- Published
- On Arc Testnet, block 70432815: 0x56b814612eb2e3e544153df3e91e1f7199106d1e430c7d8c6b653feeb9ebe9af