Cooperative mate is a family of Chess game puzzles where both sides cooperate towards a common goal. Here, we consider endgames with only black king, white king, and white rook, aiming to checkmating the black king. Your task is to provide a shortest sequence of moves leading to such mate.

  The Goal

For a given state of the game, the goal is to compute a sequence of chess piece moves leading to the fastest checkmate.

  Rules

The game state is described by the player-to-move and position of each piece: white king, white rook, and black king, formatted as white d5 g7 a6.

The goal of this puzzle is to provide a sequence of moves leading to a cooperative checkmate, according to the Chess rules. The sequence should be formatted as d5c5 a6a5 g7a7.


Victory Conditions
  • Given sequence of moves leads to the fastest checkmate possible in the current board position.
Loss Conditions
  • Given sequence of moves does not lead to a checkmate within a turn limit.
  • Given sequence of moves contains illegal move.
  • Given answer is not properly formatted.
  • Response time exceeds the time limit.

  Detailed rules

  • Given board state is always a valid Chess game position.
  • You can hide showing legal moves in the settings panel ()..

  Related puzzles

  • Adversarial variant of single rook endgames, requiring you to play as white against the black player, is available here.
  • To play full version of Chess as a bot programming game you can go here.

  Game Input

Initial input

A single line containing space-separated strings, movingPlayer being either black or white, and whiteKing whiteRook blackKing positions in column-row format, e.g. a1.

Output
A single line containing a sequence of space-separated moves (each move in a1h8 format).
Constraints
1 ≤ solution length ≤ 12
Response time ≤ 20s