{
  "patternType": "BACK_RANK_WEAKNESS",
  "description": "Classic back-rank mate with no escape squares for the king.",
  "cases": [
    {
      "id": "back_rank_rook_mate",
      "initialFen": "6k1/5ppp/8/8/8/8/5PPP/R5K1 w - - 0 1",
      "sideToMove": "white",
      "bestMove": { "san": "Ra8#", "uci": "a1a8" },
      "resultingFen": "R5k1/5ppp/8/8/8/8/5PPP/6K1 b - - 1 1",
      "expectedPattern": {
        "type": "BACK_RANK_WEAKNESS",
        "side": "white",
        "attackerSquares": ["a8"],
        "targetSquares": ["g8"],
        "explanationKey": "back_rank_mate"
      },
      "context": "No luft and the king is boxed in; the rook delivers mate on the back rank.",
      "tags": ["mate", "fundamental"]
    }
  ]
}