Logic Masters Deutschland e.V.

Many thanks to gdc for testing several earlier versions of this puzzle, and to NEWS and Scojo for testing as well.

Normal Sudoku Rules apply: Place the digits 1-9 once each in every row, column and 3×3 box.

Dynamic Fog: Some squares are covered with fog. Filling in correct digits may lift fog somewhere in the puzzle.

Chess Pieces:

• The digit on a White chess piece counts how many of the squares that the piece can legally move to contain a digit different from itself.
• The digit on a Black chess piece counts how many of the squares that the piece can legally move to contain the same digit as itself, not counting itself.

Each player has exactly 1 king and at most 8 pawns, 2 rooks, 2 knights, 2 bishops and 1 queen.

Legal moves: Legal moves exactly follow the normal rules of chess (explained below): Pieces can capture, pieces block movement, and moves that leave your king in check are not legal. White pawns start on row 8 and black pawns start on row 2, counting from the top. Castling, promotion and en-passant are not relevant in this puzzle.

All rules below are explanations of chess rules.

Avoiding checks

A move may not make it possible for an opposite-colored piece to see the same-colored king.

Example: If r1c1 is a white king, r1c2 is a white bishop, and r1c3 is a black queen, the king cannot move to r2c2, because the queen would then see the king. Also, the bishop cannot move away, as then the queen would see the king. However, if the bishop were black, it would be allowed to move away, since in that case the king and bishop are not on the same team.

Piece moving rules

For pawns, "forward" means upward (decreasing row numbers) for white pieces, and downward (increasing row numbers) for black pieces. They can move:

• A single step straight forward, if there is no piece on that square (irrespective of color)
• A single step diagonally forward, if there is an opposite-colored piece on that square.
• Two steps straight forward, if there are no pieces on the two squares in front of them (irrespective of color), and they are on their "starting square", which is row 8 for white and row 2 for black.

Pieces other than pawns can move onto, but not past pieces of the opposite color. They cannot move onto nor past pieces of the same color.

Rooks move one or more squares all horizontally or all vertically.

Bishops move one or more squares diagonally.

Queens move one or more squares either all horizontally, all vertically or all diagonally.

Kings can move a single square horizontally, vertically or diagonally.

Knights move with "knights moves", which is a single move that moves 2 squares in one direction and 1 square in an orthogonal direction. Pieces "in between" the starting and destination square do not block a knight from moving.

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