ChessLégal's mate is when White deliberately lets Black take the queen, then mates the black king with one bishop and two knights. Black grabs the queen and loses within seven moves. It's one of the most famous opening traps. One story says the 18th-century French player Légal (Philidor's teacher) once won a game with it. When you play online chess and your opponent suddenly offers you his queen, stop and ask why.
The pattern
This is the position just before the final move: White has no queen left, and the black king has been driven to e7 by the white bishop.
Square by square around the black king:
- d8, f8, d6: its own queen, bishop and pawn.
- e8, e6: controlled by the white bishop on f7.
- d7: controlled by the white knight on e5.
- f6: controlled by the white knight on d5.
- f7: the white bishop is here, but the knight on e5 protects it, so the king can't take it.
And no black piece can capture the knight on d5. The three minor pieces split up the work and cover every square.
How it happens in real games
The full trap goes like this (from the Philidor Defense):
The key is move five. The black bishop on g4 is pinning the white knight on f3, so it looks like if the knight moves, the white queen gets taken. But White moves the knight anyway and gives up the queen. After Black takes the queen, the white bishop takes on f7 with check, the black king has to go to e7 (d7 is covered by the knight on e5), and the other knight jumps to d5 to finish.
What if Black doesn't take the queen?
So after 5. Nxe5, Black loses something whatever he does. The real mistake came earlier: 3... Bg4 went out too early to pin the knight, leaving both e5 and f7 unguarded. For more Philidor Defense lines, see the Philidor Defense.
How to avoid it
- When your opponent offers his queen, calculate first. A "free" queen almost always hides a trap. Before you take, look at the checks he has next.
- Watch f7 (f2 for White). In the opening, f7 is protected only by the king, and an enemy bishop landing there gives check.
- Don't pin the knight with your bishop too early. Bg4 pinning the knight on f3 feels comfortable, but if your e5 pawn has no protection, the knight can take it and hand you the queen.
- A pin isn't absolute. A knight "pinned" by a bishop only loses the queen if it moves. It's still allowed to move. If your opponent is willing to give up the queen, it will.
Practice puzzles
Show answer
7. Nd5# The knight jumps to d5 for mate. e8 and e6 are covered by the bishop, d7 by the knight on e5, f6 by the knight on d5, and the bishop on f7 is protected by a knight.
Show answer
6. Bxf7+ Ke7 7. Nd5# The bishop takes on f7 with check, and the black king has to go to e7. Then the knight jumps to d5 for mate. Three minor pieces beat a queen.
Show answer
7. Bxf7+ Ke7 8. Nd5# The same idea: Bxf7+ Ke7, Nd5 mate. Black actually had a better choice here: instead of taking the queen last move, take the white knight on e5 with the knight from c6.
FAQ
Does Légal's mate have to go in exactly this order?
No. The point is "the bishop takes on f7 with check, and the two knights seal off the remaining squares." The opening moves can differ. In puzzle three Black has an extra knight on c6, and the result is the same.
What should Black do after the white knight takes on e5?
Don't take the queen. Take back the knight with the pawn. White will take the bishop on g4 and be a pawn up, but that's far better than getting mated. Best of all is not letting this position happen in the first place.
Does this trap work against strong players?
Rarely. Anyone who knows it won't pin the knight with a bishop while e5 is unguarded. But it's the best beginner example of "give up material for mate": having less material doesn't mean you're losing. King safety matters most.
Try it yourself
Légal's mate teaches you: before taking a big piece your opponent offers, check whether your king is safe. Go back to checkmate patterns for the other opening mates, or review check, checkmate and draws. When you're ready, play chess against a computer, and the next time your opponent offers his queen, stop and think.