{
  "patternType": "DISCOVERED_CHECK",
  "description": "Bishop steps aside to reveal a rook check along the open file.",
  "cases": [
    {
      "id": "discovered_check_rook_on_open_file",
      "initialFen": "4k3/8/8/8/8/8/4B3/4R1K1 w - - 0 1",
      "sideToMove": "white",
      "bestMove": { "san": "Bb5+", "uci": "e2b5" },
      "resultingFen": "4k3/8/8/1B6/8/8/8/4R1K1 b - - 1 1",
      "expectedPattern": {
        "type": "DISCOVERED_CHECK",
        "side": "white",
        "attackerSquares": ["e1"],
        "targetSquares": ["e8"],
        "keySquares": ["b5"],
        "explanationKey": "rook_file_discovery"
      },
      "context": "Moving the bishop from e2 to b5 exposes the rook on e1, delivering check on the e-file.",
      "tags": ["discovery", "rook_file"]
    }
  ]
}