The Open File: Alekhine's Gun Against Nimzowitsch, Checked

Part 1San Remo 1930: the champion meets the theorist

In January 1930 the casino at San Remo hosted a sixteen-player round robin. Alexander Alekhine, the reigning world champion, won it with 14 points from 15 games, three and a half points clear of Aron Nimzowitsch in second place. ^[7][6] ✓ Verified

They met in round 3, and Alekhine won by forcing Nimzowitsch to resign from a middlegame bind in which Black had almost no useful moves left. ^[6] ✓ Verified

There is an irony in it. Nimzowitsch was the great theorist of the age, the author of My System, the book that taught a generation about open files, blockade and restraint. In this game Alekhine used exactly those ideas against their author: a file, a frozen queenside and a bind.

The formation White builds on moves 21 to 26, two rooks in front and the queen behind them on the same file, is now called Alekhine's gun. Edward Winter found the name in print in a Russian textbook of 1981, which said it was probably taken from this game, and found the same idea in games as early as the 1840s. ^[4] ✓ Verified

Part 2What is an open file in chess, and when does it win?

An open file is a vertical column with no pawns of either colour on it. Rooks and queens move freely along it, so the side that controls it can bring them into the enemy camp. Controlling the file is not the goal in itself: the goal is an entry square at the far end, a square on the file (often on the seventh or eighth rank) where a rook can land safely and attack something.

A file is worth most when three things are true: the opponent cannot put a rook on it to challenge yours, there is an entry square the opponent cannot cover, and there is a target behind it, a pawn on the seventh rank or a piece that must be defended. If any of the three is missing, an open file can be a road to nowhere. ◐ Inferred

Part 3The opening: how a French Winawer opened the c-file

Nimzowitsch chose the Winawer French (the openings section covers the French Defence) and Alekhine answered 4...c5 with the quiet 5.Bd2 and 6.Nb5, aiming the knight at d6 and swapping off Black's good dark-squared bishop. Black then followed a familiar French plan: trade the bad light-squared bishop with ...b6 and ...Ba6, and pressure White's centre.

Stockfish already likes White by most of a pawn here, and most of the edge came from one move: after 10...Qd7 White gained space with 11.a4 and 12.b4 before Black had finished developing. Stockfish preferred 10...Nbc6 first. ✓ Verified

Part 4The plans: White's file against Black's blockade

After 18...N8e7 the structure is fixed for the rest of the game. White owns more space everywhere; the c-file is open; the white pawn on a6 has frozen Black's a7 and b6 pawns. Black's position is solid but has one weakness that matters: the knight on c6, which stands on the file and is pinned to the queen by the bishop on b5. ◐ Inferred

Part 5The critical moments: moves 13 to 15

Most accounts of this game linger on moves 21 to 32, when the gun is built and Black runs out of moves. Stockfish puts the decisive turns much earlier. Try each position before opening the answer.

Part 6The turning point: 15...Nc8 and the pawn on a6

Here the game was decided, nine moves before the gun was built. Black has one chance to stop White's a-pawn, and it is a quiet pawn move.

The pressure White exerts on the file is crushing.

Part 7What Nimzowitsch could have done

Black's position after 13.cxb4 was worse but healthy. Stockfish's defence follows one idea twice: deal with the threat to the structure before the threat from the pieces. On move 14 that meant trading the d6 knight with ...Nf5 (or stopping the a-pawn with ...a5); on move 15 it meant stopping the a-pawn with ...a6 before it could reach a6. ✓ Verified

Part 8A different angle: was it really zugzwang?

Alekhine presented the finish as a zugzwang, a position where Black would be fine if allowed to pass and loses only because every legal move makes things worse. In 1972 Wolfgang Heidenfeld, in the British Chess Magazine, disallowed the game as an example of zugzwang despite Alekhine's claim. ^[5] ✓ Verified

Stockfish can test the claim directly by giving the move back to White in the final position. If White were not winning there, the zugzwang label would be exact. The number above the board says White is winning anyway. ✓ Verified

Stockfish also shows that the waiting moves were not needed. After 30...h5 it prefers 31.Ng5, threatening the e6 pawn and the f7 square: if Black grabs a pawn with 31...Nxd4, then 32.Rxc7 Rxc7 33.Nf7+ Ke8 34.Bxd7+ Kxf7 35.Rxc7 leaves White with an extra queen. The squeeze worked; a direct win was also there. ✓ Verified

Perhaps Alekhine chose 15.a5 over the engine's 15.Qc3 because the clamp with a6 was easier to judge at the board than an open fight for the file; the record does not say. Either way, the game shows how strong a slow, permanent advantage can be against an opponent who must find exact moves to escape it. ? Speculative

Part 9How to use an open file in your own games

Open files appear in almost every game, but most players treat them as decoration: a rook goes to the file and stays there. Alekhine's game gives a recipe that works at any level. For a related plan with the seventh rank, see the rook ending Capablanca won against Tartakower; for a squeeze built on space, see Karpov against Unzicker.

• Before taking the file, ask what the rooks will attack once they are on it.
• Fix the target first, then bring the rooks; a target that can move away is not a target.
• As the defender, contest the file early with a rook and keep the entry squares covered by pawns, not pieces.
• As the defender, stop the pawn that would freeze your structure before you deal with the pieces.

Your turnPractise it

Set each position up, decide your plan before you look, then play it out against Stockfish to see whether it holds.

Part 10What to take from this game

• A file needs a destination. Control of the c-file only mattered once c7 and c6 were targets Black could not move.
• Structure wins files. 17.a6 froze Black's queenside, and from then on the file belonged to White.
• The famous move was not the decisive one. Stockfish says Black was lost after 15...Nc8, before the gun was built.
• Count the pieces. White could bring four attackers to c6; Black had four defenders and no spare move.
• Defend the structure first. 14...Nf5 and 15...a6 were Black's saving moves: remove the intruder, then stop the pawn.