Epaulette mate

In this pattern, the king has one of its own pieces immediately on each side. In the classic form those pieces are rooks, although other pieces can serve the same role. They resemble uniform epaulettes and, more importantly, prevent the king from moving sideways.

Two friendly pieces seal the sides

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a1

b

c

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The queen on c5 checks the king on a5 along the fifth rank.

The queen checks and the pawns seal the sides

The queen on c5 checks the king on a5 along the fifth rank. That same line covers b5, while b4 and b6 are the other two controlled flight squares. Black's pawns on a4 and a6 block the king's sides; there is no legal capture, interposition, or escape.

1. The queen on c5 checks the king on a5 along the fifth rank.
2. The queen controls b4 and b6; b5 is covered by the same checking line.
3. Black's pawns on a4 and a6 form the epaulettes by occupying the two squares immediately beside the king.

A queen usually checks from in front of the king or from a nearby line and covers the other escape squares. The blocking pieces do not need to be attacked. It is enough that they belong to the defender and occupy squares their king would otherwise use.

For the position to be mate, the king must have no escape, the checking piece must be impossible to capture, and no piece may be able to block the check. A side piece being able to move in some other situation is not enough: while the king is in check, that move must answer the threat immediately.