EndgamesPlay as White

The Trebuchet

Learn the trebuchet — two blocked pawns, each attacked by the enemy king, where the side that has to move loses its pawn and the game.

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Introduction

The trebuchet is a mutual zugzwang — a position where whoever has to move loses. Two pawns block each other (here White's e4 and Black's e5), and each king stands next to both pawns: it guards its own pawn and attacks the enemy pawn. Neither king can take, because the other king guards that pawn. But a king that has to move must step away from its own pawn, and the enemy king takes it next move. Right now Black's king on d4 already attacks e4, and White's king on g6 is not guarding it yet. White has exactly one winning move: step into the trebuchet so that it is ♗︎lack who has to move. Every other move loses the e4-pawn, and with it the game.

Lesson Content

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1. ♔︎f5

Guard your pawn and attack the black one at the same time — so that Black has to move.

♔︎f5 — the trebuchet, with Black to move. The king on f5 guards e4 and attacks e5, exactly as Black's king on d4 guards e5 and attacks e4. Neither pawn can be taken, so Black must move the king — and every king move leaves e5 without a guard. White wins that pawn next move and then queens the e-pawn. This is the only winning move. Any other king move leaves e4 unguarded, Black takes it with ♔︎xe4 and it is Black who wins.

ZugzwangPassed Pawn

Alternative Moves

♔︎f6 — Loses! ♔︎f6 attacks e5 but no longer guards e4: Black takes it with ♔︎xe4, the e5-pawn stays guarded, and Black wins the game.

♔︎g5 — Loses! ♔︎g5 does not guard e4: Black takes it with ♔︎xe4, and Black wins the game.

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1. ..♔︎c5

Black is in zugzwang: the king has to move, and every square it can reach leaves e5 without a guard. ♔︎c5 is the longest defence — the king heads for d6 and d7 to get back in front of the white pawn. But the e5-pawn is now unguarded.

Zugzwang

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2. ♔︎xe5

Black's king had to leave its pawn — punish that and win material.

♔︎xe5 — White wins the pawn. Now it is King and Pawn against King, and the white king stands in front of its pawn. That is the winning set-up: with the king ahead of the pawn, the king clears the way and the pawn walks to e8 and becomes a queen.

Passed PawnKey Squares

Alternative Moves

♔︎f6 — Draws! ♔︎f6 does not take the pawn, so Black plays ♔︎d6 and guards e5. Even if White wins that pawn later, Black's king stands in front of White's pawn and blocks it, and the game is a draw.

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2. ..♔︎c6

Black's king heads for d7 and e7, the squares in front of the pawn. A king in front of the pawn blocks it and draws the game. It cannot use d6: White's king on e5 covers it.

Key Squares

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3. ♔︎e6

Keep your king ahead of the pawn and keep Black's king out of its path.

♔︎e6 — the king steps onto the sixth rank, in front of its pawn. From e6 it covers d7, e7 and f7, so Black's king can never get in front of the e-pawn, and the pawn will queen.

Key Squares

Alternative Moves

♔︎d4 — Draws! ♔︎d4 leaves the squares in front of the pawn, so Black's king gets there first. A king in front of the pawn blocks it, and the game is a draw.

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3. ..♔︎c5

Black waits on the c-file. The king cannot get in front of the pawn, because White's king guards d7, e7 and f7 — so the pawn will queen.

Key Squares

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4. e5

Your king controls the road ahead — start moving the pawn.

e5 — the pawn starts its walk to e8, and the king on e6 clears the way for it.

Passed Pawn

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4. ..♔︎c6

Black's king goes to c6, but White's king covers d7, so it still cannot get in front of the pawn.

Passed Pawn

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5. ♔︎f6

Make room for the pawn without letting the black king into its path.

♔︎f6 — the king steps aside so the pawn can advance to e6, and it keeps covering e7 and f7. Even if Black's king reaches d7, it cannot stop the pawn from queening.

Passed PawnKey Squares

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5. ..♔︎b5

Black has no defence left. Every king move loses, and the king simply waits.

Passed Pawn

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6. e6

Keep the pawn moving.

e6 — the pawn is two squares from queening, and the king on f6 guards it and the square in front of it.

Passed Pawn

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6. ..♔︎c6

Black's king comes back to c6. It cannot step to d7 yet, because the e6-pawn covers that square.

Passed Pawn

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7. e7

One more step toward the last rank.

e7 — the pawn reaches the seventh rank, guarded by the king on f6. Soon it queens.

Passed Pawn

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7. ..♔︎d7

♔︎d7 — Black's king attacks e8, the square where the pawn wants to queen.

Passed Pawn

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8. ♔︎f7

Black's king is close to the queening square — guard your pawn and keep Black's king away from e8.

♔︎f7 — the king covers e8 and keeps guarding the pawn on e7. Black cannot stop the pawn from becoming a queen next move.

Passed PawnKey Squares

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8. ..♔︎c6

Black has no defence left. The pawn queens next move.

Passed Pawn

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9. e8=♕︎+

Make a queen!

e8=♕︎+ — promotion, with check. King and Queen against King is an easy win. The game was decided on move 1, when White's king stepped into the trebuchet with Black to move and Black had to give up the e5-pawn.

Passed PawnZugzwang

Key Takeaways

In a trebuchet, both kings guard their own pawn and attack the enemy pawn — whoever has to move loses
Don't just attack the enemy pawn: first make sure your own pawn is guarded, or the other king takes it
Count who will be to move when the trebuchet appears, and step into it so that your opponent has to move
After winning the pawn, keep your king in front of your own pawn so the defending king can never block it

Now play it through

Step through every move on a real board, try the wrong ones, and ask Knighty why they fail.

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Related Lessons

Stalemate Trap: Queen vs f-Pawn

Two Pawns vs One

Key Squares

Summary

You've learned the trebuchet: two pawns block each other, each king guards its own pawn and attacks the enemy pawn, and the side that has to move loses its pawn. White's only winning move was ♔︎f5, which reached the trebuchet with Black to move. Black's king had to leave e5, White took the pawn, kept the king in front of its own pawn and pushed the pawn to e8.

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Triangulation

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