Légal's Mate is the most elegant trap in the 1.e4 e5 openings — White sacrifices the queen and checkmates with three minor pieces. It punishes a careless pin: Black pins the f3-knight with …Bg4, assumes it's frozen, and walks into 'the pin that wasn't there.' Named after the 18th-century French master Sire de Légal, Philidor's teacher.
When Black pins the f3-knight with …Bg4 but leaves the e5-pawn loose, White can play Nxe5! — and if Black grabs the queen, Bxf7+ and Nd5# mate with bishop and two knights.
A pin only matters if moving the pinned piece loses more than it gains. After 5…Bg4 6.h3 Bh5?, White uncovers the trick with 7.Nxe5! If Black plays the 'obvious' 7…Bxd1, winning the queen, then 8.Bxf7+ Ke7 9.Nd5# — the king is hemmed in and three minor pieces deliver mate. The queen was worth less than the mating net. (If Black declines and plays 7…Nxe5 instead, White is simply a clean pawn up with the better game.)
5… Bh5 — 5…Bg4 pins the knight, and after 6.h3 the losing move is 6…Bh5??, stubbornly keeping the pin. Black trusts that the f3-knight is paralysed — but it isn't. The safe move is 6…Bxf3, trading the bishop off before anything happens.
Don't treat a pin as permanent. When White challenges your bishop with h3, ask: 'what happens if that knight moves anyway?' Here, because e5 is hanging and f7 is soft, the knight jumps with deadly effect, so Black should release the tension with …Bxf3. More generally, be wary of pinning before your own centre (…e5) is secure.
Yes — in this exact position it forces checkmate, so giving up the queen is completely correct. But it only works because Black cooperated with 6…Bh5 and then 7…Bxd1. With 6…Bxf3, there's no trap at all.
Then White has simply won a pawn for nothing: after 7.Nxe5 Nxe5 8.Qxh5, White is a healthy pawn up with a great position. The defender loses either way once 6…Bh5? is played.
Sire de Légal de Kermeur, a leading French player of the 1700s and the teacher of the great Philidor. The mating pattern that carries his name is one of the oldest known traps.
A trap only works if your opponent makes the mistake — strong players sidestep these, which is why each page also shows how to avoid it. Every line here is checked legal with the same engine the board runs, and every checkmate is verified.