Classic Chess Sacrifices: Bxh7+ and the Exchange

A sacrifice is the voluntary surrender of material in return for something worth more: a checkmate, an attack your opponent can't contain, or a lasting positional advantage. The classic sacrifices — such as Bxh7+, known as the Greek gift, and the exchange sacrifice (a rook for a minor piece) — keep recurring because they grow out of the same structures. If you know each pattern and its conditions, you'll spot it at the board and, just as important, you'll know when it does not work.

Calculated versus speculative sacrifices

Not all sacrifices are alike. It helps to separate two kinds:

• Calculated: you can see to the end. The sacrifice is followed by a forced sequence (checks, captures, mating threats) and you know you'll win the material back with interest or deliver mate. The Bxh7+ in this article is that kind.
• Speculative or positional: you can't see a concrete end, but you judge that the compensation — an exposed enemy king, more active pieces, a wrecked pawn structure — is worth the material. Exchange sacrifices are usually of this kind.

The first demands calculation. The second demands judgment. Both demand pattern knowledge, because nobody calculates from scratch an idea they have never seen.

The Greek gift: Bxh7+

The Greek gift is the most famous attack against a kingside-castled king. The bishop takes on h7 with check, the king recaptures, the knight jumps to g5 with check and the queen comes in along the h-file.

Before you sacrifice, check the conditions. In this model position all of them are present:

1. The bishop on d3 aims at h7, and the h7 pawn is defended only by the king.
2. There is no black knight on f6. White's e5 pawn takes that square away; a knight on f6 would guard h7 and h5.
3. The knight reaches g5 safely. Black's dark-squared bishop is far away on a5 and can't reach g5, and the h4 pawn supports the knight.
4. The queen arrives fast on the h-file: d1 to h5 in one move.
5. The escape squares are covered: the c1 bishop sits behind the knight on the diagonal to h6, ready for a discovered check, and the h4 pawn can advance with check.

The main line is 1.Bxh7+! Kxh7 2.Ng5+, and now the black king has four squares. None of them saves it:

• 2...Kg8 — mate in two; solve it in the first exercise below.
• 2...Kh8 3.Qh5+ Kg8 4.Qh7#.
• 2...Kg6 3.h5+! — if 3...Kf5, then 4.g4#. If 3...Kh6, 4.Nxe6+ is a discovered check from the c1 bishop and, as in the next line, 5.Nxc7 wins the queen.
• 2...Kh6 3.Nxe6+ — a discovered check from the c1 bishop. The knight on e6 also hits the queen on c7, and 4.Nxc7 wins it.

What if Black declines the bishop with 1...Kh8? Then White can simply retreat with 2.Bd3: a pawn up, with Black's castled position opened. A sacrifice whose worst case is winning a pawn is an excellent deal.

Queen sacrifices that end in mate

The most spectacular sacrifices give up the queen, and they almost always follow known mating patterns:

• Smothered mate, which you saw in deflection and decoy: the queen offers itself on g8 (or next to the king), a rook is forced to capture and plugs the last flight square, and the knight mates a king boxed in by its own pieces.
• Anastasia's mate: with a knight on e7 covering g8 and g6, the queen takes on h7, the king recaptures and a rook mates along the h-file.
• Back-rank deflection: the queen is given up to remove the only defender of the eighth rank, and the rook comes in with mate.

The exercises below feature two of these patterns. In every one of them, the sacrifice works only because every move is forced: check, forced capture, mate.

The exchange sacrifice

"The exchange" is the difference between a rook and a minor piece. Sacrificing the exchange means giving a rook for a bishop or a knight. On the point count you lose about two, but the rook is not always the most useful piece in the position. The most common reasons:

• Wrecking the king's pawn cover. In the Sicilian, ...Rxc3 is a classic: after bxc3, White's queenside castled position is left with doubled, isolated pawns, and the e4 pawn loses a defender.
• Eliminating a key piece, such as the knight that defends the king or the bishop that controls the squares of one color.
• Gaining pawns and initiative: the exchange often comes back with a pawn or two and very active pieces.

Exchange sacrifices are usually positional: there is no mate in sight, and the evaluation depends on how long the compensation lasts. Former world champion Tigran Petrosian became famous for exchange sacrifices of this kind, played to neutralize his opponent's play.

How to decide whether a sacrifice works

Before giving up material, ask these questions in this order:

1. How many attackers and how many defenders? Count the pieces taking part in the attack and the ones that can defend the king within two or three moves.
2. Are the moves forcing? Checks and captures limit the replies and make calculation possible. Quiet moves give your opponent time.
3. What if they decline? Many sacrifices can be declined. Calculate the refusal too.
4. What is the worst case? If it goes wrong, do you lose a piece and the game, or are you left with compensation?

Exercises

Frequently asked questions

Why is Bxh7+ called the Greek gift?

The name alludes to the Trojan horse, the "gift from the Greeks": the bishop on offer hides an attack.

When does Bxh7+ fail?

When there is a defender on f6, when Black can capture the knight on g5, when the white queen can't reach the h-file, or when the black king has a safe escape via f8 or g6.

What does sacrificing the exchange mean?

Giving a rook for a minor piece (bishop or knight). In return you aim to wreck the king's pawn cover, eliminate a key piece, or win pawns and the initiative.

How should I train sacrifices?

Solve mating-pattern and king-attack exercises, always calculating the most stubborn defense — including declining the sacrifice.