Opening LabLegal's Mate
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Opening Traps/know them from both sides/C50/You play Black

Legal's Mate

The pinned knight walks away and leaves the queen hanging. Take her, and it is mate in two.

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Move 0 of 16 · Black up
the moveattackscheckyour note

Play a move on the board and I’ll answer it. ← → to step.

1.2.3.4.5.6.7.8.
StartBefore the first move

The starting position. White moves first, and that single tempo is the whole reason opening theory exists.

The moves in the text are buttons. Press one and the board beside it shows the position.

The idea in one paragraph

8.Nd5#

The oldest trap in the book. In the Semi-Italian, , Black pins the f3-knight with ...Bg4 and keeps the pin after with . Then the knight simply walks out of it: leaves the queen on d1 hanging, and taking her () is mate in two, . Even the only defence, , costs Black a pawn. The cure comes a move earlier: , giving up the pin before it turns into a trap.

The pawn structure

There is no pawn structure here, only three squares. f7, guarded only by the black king, which the c4-bishop and the e5-knight attack together. d5, where the c3-knight mates from. And the d1–h5 diagonal, the line of a pin that only holds while moving the knight costs more than the queen.

The plans

8.Nd5#

♔ White’s plans

  • Against the Semi-Italian pin, ask the question with , the engine's first choice anyway.
  • If the bishop stays on the diagonal with , walk out of the pin: The queen is bait.
  • After the mate is . After , and the queen check on b5 win a clean pawn.

♚ Black’s plans

  • Answer with (the engine's choice) or . Either way there is no pin left to walk out of.
  • If you have already played and the knight takes on e5, do not take the queen: is a pawn down, but it is a game.
  • After , block the queen's line to f7 with ...Nf6, and trade off the c4-bishop with ...Na5.

Traps and things that lose games

Legal's Mate

8.Nd5#

. The cure: .

Trap 2

9.Qxc4

The only defence after : , a pawn down.

Its cousins

the Elephant Trap, the same pin-that-is-not-a-pin in the Queen's Gambit; and the Blackburne Shilling, a trap from the same Italian position for the other side.

Every beginner, from both chairs. It is the first trap most players learn, and it still works in fast games because 5...Bh5 looks like the most natural move on the board.

Your learning path: Legal's Mate

Beginner

One trap from both chairs: walk out of the pin as White, and refuse to keep it as Black.

  1. FoundationOne sitting

    Goal. Spring it, mate with it, and never fall for it.

    • The bait: 6.Nxe5 leaves the queen hanging on purpose.
    • The mate: 7.Bxf7+ Ke7 8.Nd5#, and which piece covers each of the king's squares.
    • The only defence: 6...Nxe5, still a pawn down.
    • From Black's chair: 5...Bxf3.
    DrillDrill all three chapters, then set up the position after 5...Bh5 and say, before moving, what each of Black's replies to 6.Nxe5 leads to.
    Common mistakeWalking the knight out of the pin before Nc3 is in. The mate needs the knight on c3 to reach d5.
    Move on whenYou can play the mate from memory, and as Black you play 5...Bxf3 without thinking.

Whose games to study

Wikipedia's Légal Trap article gives the history: Légal de Kermur, eighteenth-century Paris. Every evaluation here comes from Stockfish at depth twenty.

What to learn after this

The Italian Game course, and the Fried Liver and Blackburne Shilling courses for the other f7 tricks from the same position.