Alekhine's gun is a formation in chess

Chess

Chess is a two-player board game played on a chessboard, a square-checkered board with 64 squares arranged in an eight-by-eight grid. It is one of the world's most popular games, played by millions of people worldwide at home, in clubs, online, by correspondence, and in tournaments.Each player...

 named after the former World Chess Champion

World Chess Championship

The World Chess Championship is played to determine the World Champion in the board game chess. Men and women of any age are eligible to contest this title....

, Alexander Alekhine

Alexander Alekhine

Alexander Alexandrovich Alekhine was the fourth World Chess Champion. He is often considered one of the greatest chess players ever.By the age of twenty-two, he was already among the strongest chess players in the world. During the 1920s, he won most of the tournaments in which he played...

. This formation was named after a game he played against another illustrious Grandmaster

International Grandmaster

The title Grandmaster is awarded to strong chess players by the world chess organization FIDE. Apart from World Champion, Grandmaster is the highest title a chess player can attain....

, Aaron Nimzowitsch in San Remo

Sanremo

Sanremo or San Remo is a city with about 57,000 inhabitants on the Mediterranean coast of western Liguria in north-western Italy. Founded in Roman times, the city is best known as a tourist destination on the Italian Riviera. It hosts numerous cultural events, such as the Sanremo Music Festival...

 1930, ending with Alekhine’s victory. The idea consists of placing the two rooks

Rook (chess)

A rook is a piece in the strategy board game of chess. Formerly the piece was called the castle, tower, marquess, rector, and comes...

 stacked one behind another and the queen

Queen (chess)

The queen is the most powerful piece in the game of chess, able to move any number of squares vertically, horizontally, or diagonally. Each player starts the game with one queen, placed in the middle of the first rank next to the king. With the chessboard oriented correctly, the white queen starts...

 at the rear. This can lead to massive damage to the opponent as it usually marks the beginning of the final assault (in this case it was only four moves before resignation). In rare cases it can be two queens and one rook on the same file.

The original "Alekhine's gun" game

Here is the game that spawned Alekhine’s gun:

Alexander Alekhine vs. Aron Nimzowitsch:

1. e4 e6 2. d4 d5 3. Nc3 Bb4 4. e5 c5 5. Bd2 Ne7 6. Nb5 Bxd2+ 7. Qxd2 0–0 8. c3 b6 9. f4 Ba6 10. Nf3 Qd7 11. a4 Nbc6 12. b4 cxb4 13. cxb4 Bb7 14. Nd6 f5 15. a5 Nc8 16. Nxb7 Qxb7 17. a6 Qf7 18. Bb5 N8e7 19. 0–0 h6 20. Rfc1 Rfc8 21. Rc2 Qe8? 22. Rac1 Rab8 23. Qe3 Rc7 24. Rc3 Qd7 25. R1c2 Kf8 26. Qc1
(See diagram. This is the point at which Alekhine forms the gun.)
26. … Rbc8 27. Ba4
(Threatening 28. b5, winning the pinned

Pin (chess)

In chess, a pin is a situation brought on by an attacking piece in which a defending piece cannot move without exposing a more valuable defending piece on its other side to capture by the attacking piece...

 knight)
27. … b5 28. Bxb5 Ke8 29. Ba4 Kd8
(Guarding c7, so that the knight can move away on 30. b5)
30. h4!
(But now all Black's pieces are committed to the defence against the gun, and he is running out of moves.)
30. … h5 31. Kh2 g6 32. g3 (Zugzwang

Zugzwang

Zugzwang is a term usually used in chess which also applies to various other games. The term finds its formal definition in combinatorial game theory, and it describes a situation where one player is put at a disadvantage because he has to make a move when he would prefer to pass and make no move...

) 1-0

Six years later, in 1936, William Winter

William Winter (chess player)

William Winter was a British chess player. He won the British Open Chess Championship in 1934 and the British Chess Championship in 1935 and 1936. An acolyte of Siegbert Tarrasch, his sound, strategic play enabled him to defeat a number of the world's top players, including David Bronstein, Aron...

 was defeated by Alekhine in Nottingham, who used Alekhine's gun again to secure the victory. Since then, chess players have learned much about using and guarding against this formation. However, some international games are still lost and won by the force of this tactic.