Blind swine mate

Blind swine mate is an informal name for a pattern created by two rooks that have reached the seventh rank, the horizontal row immediately before the opponent's home rank. For Black, the equivalent picture uses rooks on Black's second rank. The rooks are commonly side by side and protect each other.

One rook checks along the king's file. The other controls the neighboring square and protects the checking rook. Together with the edge of the board and often a defending piece that acts as a stopper, they restrict the king to a two-by-two box. The result is checkmate only when the king is attacked and no legal reply removes the attack.

Closed cage

The stopper completes the cage

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The rook on a7 checks the king on a8.

The b8 square decides the mate

The two-by-two cage is closed by three distinct functions: check, protection between the rooks, and a defending piece occupying the remaining exit.

1. The rook on a7 checks the king on a8.
2. The rook on c7 controls b7 and protects the rook on a7 along the same line.
3. The black rook on b8 occupies the only remaining flight square.

The pattern is not merely a series of alternating rook checks. The rooks must prevent the king from crossing to the open side. If one flight square is not controlled, the king may escape, and repeated checks may produce no mate.

Open side

One open square changes the verdict

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StartKb8Rcb7#

The rook on a7 checks the king on a8.

The cage still has an exit

The battery retains the check and protection between the rooks, but the cage is incomplete. The b8 square remains available as a legal reply.

1. The rook on a7 checks the king on a8.
2. The rook on c7 controls b7 and protects the rook on a7 along the same line.
3. The king can escape to b8, a free square controlled by neither white rook.

It is different from ladder mate. In a ladder mate, two long-range pieces gradually drive the king toward an edge from parallel ranks or files. Blind swine mate has the characteristic setup of connected rooks on the seventh rank with the king already trapped near its back rank.