FA-82352 / Chess move legality / Member archive

Knight captures its own side but not the enemy · case 02

The knight may land on a friendly bishop but not capture an enemy pawn.

Member previewVariant 2 · 3 implementations · 8 checks per implementation

Case contract

Input: {"board": {square: piece}, "from": square of a knight}. Squares are indexed 0..63 with a1=0, h1=7, a8=56. Return the sorted list of pseudo-legal knight destinations: on the board, not wrapping across the a/h file edge, and not occupied by a piece of the knight's colour.

Why this case matters

Move validators gate every move in engines, servers and arbiters; accepting an illegal move or rejecting a legal one corrupts the game record.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
black knight own pieces	`["c4", "c6", "d3", "d7", "f7", "g4", "g6"]`	`["c6", "d3", "f3", "f7", "g4", "g6"]`	Failed

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