Légal's mate: the queen is given away, and the minor pieces mate

The trap

Black's bishop has pinned White's knight on f3 to the queen. It looks as if the knight can't move. But it moves anyway, and takes a pawn on e5. If Black takes the queen, a check on f7 follows, and then mate with the other knight.

The mate is given by three minor pieces: the bishop on f7 and the knights on e5 and d5. Black's own pieces are in the king's way, and White's queen isn't needed at all. In German it is also called the Seekadettenmatt, the sea cadet's mate.

How to avoid it

Black doesn't have to take the queen. If Black takes the knight instead, White has won a pawn, but there is no mate. The lesson is bigger than the trap: a pin against the queen is not an absolute pin. The knight may move, and sometimes that is the whole point. Read about the difference under pin.

An old trap with an uncertain history

The trap is named after the eighteenth-century French player Legall, whose name is spelled in several ways: Légal, Legall, Legall de Kermeur. According to a baptism register in Versailles, he was born in 1702. It is often said that he gave the mate against a Saint Brie in Paris in 1750. But the oldest version we have found, in the English writer George Walker's book of 1835, gives neither year nor city. The opponent is called only M. de St. B***, and he had been given the odds of one of White's rooks.

The moves differ too. In Walker's version the move order is different, and Black has a knight on c6 instead of a pawn on g6. The version most often given, against Saint Brie, has the moves above, but there too Legall plays without one of his rooks. Here we show the trap with all the pieces on the board, because that is how it can turn up in your own games. Chess historians have asked where each version was first printed, and nobody knows for sure. The only thing everyone agrees on is the ending.

See it coming, and defend

• A pin against the queen is no guarantee. The piece may move. Ask yourself what happens if it does.
• Calculate before you take the queen. That is the hardest thing of all: to leave the queen alone when your opponent offers it. Go through every check that follows.
• The square f7. At the start of the game only the king protects it. A bishop that captures there with check is the start of many mates, the scholar's mate among them.
• Develop before you pin. Black's bishop came out early, and Black's kingside was still at home.

Updated November 14, 2026