Legal's Mate Trap
A brilliant queen sacrifice followed by a stunning three-piece checkmate that punishes an early bishop pin in the Philidor Defense.
Published 2026-02-01 | Last verified 2026-02-12
Professor Archer says: Legal's Mate is perhaps the most beautiful checkmate pattern that can occur in the opening. You sacrifice your queen, the most powerful piece, and then deliver checkmate with three minor pieces. I remember the first time I showed this to a class of beginners: half of them gasped, and the other half thought I had made a mistake. That reaction is exactly why this trap is so effective. It looks like madness, but it is pure logic.
What Is Legal's Mate?
Legal's Mate is a checkmate pattern named after Sire de Legal, an 18th-century French chess master. It arises from the Philidor Defense after 1. e4 e5 2. Nf3 d6 3. Bc4 Bg4 4. Nc3 when Black plays carelessly.
The trap springs when Black pins the knight on f3 with the bishop on g4, and White plays Nxe5. If Black takes the queen with Bxd1, White plays Bxf7+ Ke7, followed by Nd5#. Three minor pieces combine to deliver a stunning checkmate.
The checkmate pattern features the bishop on f7 giving check, the knight on d5 delivering the final blow, and the knight on e5 covering the escape squares. It is one of the most aesthetically pleasing checkmate patterns in chess.
The Checkmate Position
After Black greedily captures the queen with Bxd1, White unleashes the combination: Bxf7+ Ke7 Nd5#. The king on e7 is trapped: f8 and d8 are blocked by Black's own pieces, f6 is covered by the knight on e5, d6 is covered by the knight on d5, and the bishop on f7 controls e6 and e8.
Every white minor piece plays a crucial role in the mating net. Remove any one of them and the checkmate would not work. This perfect coordination is what makes Legal's Mate so instructive and beautiful.
After Bxd1?? - White plays Bxf7+ Ke7 Nd5# for a stunning checkmate.
How Black Should Respond
The simple defense is to not take the queen. After 4. Nc3 and the threat of Nxe5, Black should retreat the bishop from g4 or play a solid developing move. If Black recognizes that the queen sacrifice leads to checkmate, there is no reason to walk into the trap.
More fundamentally, Black should be cautious about the early Bg4 pin. While pinning the knight is a common idea, doing so before developing other pieces can lead to exactly these kinds of tactical problems. The bishop on g4 is committed to a square where it can become a liability.
The broader lesson is to calculate deeply before capturing material, especially when a sacrifice seems too generous. If your opponent offers you their queen, there is almost certainly a reason. Take the time to find it.
Legal's Mate FAQ
Who was Sire de Legal?
Sire de Legal (also written Legal de Kermeur) was a French chess master in the 18th century. He was the teacher of Francois-Andre Danican Philidor, who would become the strongest player of his era. Legal's most famous legacy is this beautiful checkmate pattern.
Can Legal's Mate occur in other openings?
The exact pattern is specific to positions where Black has pinned the knight on f3 with a bishop on g4. However, the general concept of a queen sacrifice leading to a minor piece checkmate can occur in many different positions.
Why does Black fall for this trap?
Taking the queen is instinctive for most players. The idea of declining a free queen goes against every beginner impulse. Additionally, the three-piece checkmate requires seeing several moves ahead, which is challenging under time pressure.
Professor Archer says: The lesson of Legal's Mate extends far beyond this specific position. It teaches you that the queen is not sacred. If sacrificing it leads to checkmate, then the sacrifice is not a loss but a winning move. Strong players understand that every piece, including the queen, is a resource to be invested for a return. Legal's Mate is the most dramatic demonstration of that principle.
Quick Quiz
After 1. e4 e5 2. Nf3 d6 3. Bc4 Bg4 4. Nc3 Nc6 5. Nxe5 Bxd1??, what is White's winning move?
- Bxf7+, starting the checkmate sequence with Ke7 Nd5# (Correct) - Correct. Bxf7+ forces the king to e7, and then Nd5# delivers checkmate. The three minor pieces create a perfect mating net that the king cannot escape.
- Nxc6, winning the knight - Winning a knight would be trivial compared to the checkmate available. Bxf7+ leads to forced mate, which is far superior to winning a piece.
- Kxd1, recapturing the bishop - Recapturing the bishop would leave White down a queen for a knight. The much stronger move is Bxf7+ which leads to a forced checkmate.
- Nd5, threatening the fork - While Nd5 is a strong square for the knight, the correct sequence starts with Bxf7+ which forces the king to e7 before Nd5# delivers mate. The order matters.