Alekhine's Defence is a chess opening that begins with the moves: Black tempts White's pawns forward to form a broad pawn centre, with plans to undermine and attack the white structure later in the spirit of hypermodern defence.

Grandmaster Nick de Firmian observes of Alekhine's Defence in MCO-15 (2008), "The game immediately loses any sense of symmetry or balance, which makes the opening a good choice for aggressive fighting players.

The opening is named after Alexander Alekhine, who introduced it in the 1921 Budapest tournament in games against Endre Steiner[2] and Fritz Sämisch.

[3][4] Four years later, the editors of the Fourth Edition of Modern Chess Openings (MCO-4) wrote: Nothing is more indicative of the iconoclastic conceptions of the 'hypermodern school' than the bizarre defence introduced by Alekhine ... .

Although opposing to all tenets of the classical school, Black allows his King's Knight to be driven about the board in the early stages of the game, in the expectation of provoking a weakness in White's centre pawns.

[5]Alekhine did not consider himself part of a hypermodern revolution, however, and was quoted as referring to the hypermodern school of thought as "this cheap bluff, this shameless self-publicity", preferring to view such moves as adjustments or exceptions to the standard chess theory of central placement and control.

For instance, Bobby Fischer used it in two games against Boris Spassky in the World Chess Championship 1972, and Viktor Korchnoi also included the defence in his repertoire, leading to its respectable reputation.

De Firmian observes, "The fashion could quickly change if some champion of the opening takes up the cause, as the results Black has obtained in practice are good.

Currently, GMs Alexander Shabalov and Artashes Minasian use the opening with regularity, while Levon Aronian, Michael Adams, and Hikaru Nakamura will use it on occasion.

Magnus Carlsen does not employ the opening frequently but he has used it occasionally in competitive games, most notably to defeat the former world chess champion Veselin Topalov at Linares 2008.

The Four Pawns Attack is White's most ambitious line against the Alekhine's, and the variation which perhaps best illustrates the basic idea behind the defence: Black allows White to make several tempo-gaining attacks on the knight and to erect an apparently imposing pawn centre in the belief that it can later be destroyed.

The Four Pawns Attack is not particularly popular because many White players are wary of entering a sharp tactical line that Black may have prepared.

The third recapture 5...Qxd6 is also possible since the fork 6.c5 can be answered by 6...Qe6+, but the line is considered inferior since Black will sooner or later need to deal with this threat.

[9] In the sharper 5...cxd6 line, Black usually aims to attack and undermine the white pawn on d4, and possibly c4 as well.

Cox gave the game Jainy Gomes–Guillermo Soppe, São Paulo 2001[10] to illustrate Black's intentions.

White's setup delays kingside development so that Black has trouble developing pieces in a fashion that harasses White's pieces and assails the centre pawns; for instance there is no knight on f3 which can become a target after ...Bg4, and no bishop on d3 which may be a target after ...Nc6–e5.

loses the knight due to the 13.Rd1 pin) when Black must play carefully to unentangle and challenge the white pawn on c5.

[9] The Voronezh was recommended by John Emms and noted as a big problem by Nigel Davies,[11] leading many players to opt for the more solid 5...exd6 line.

[9] Although the 5...exd6 structure resembles the drawish Exchange French, Black can make several attempts to imbalance the position.

If White replies with c5, Black can respond with the unusual-looking ...Nc8 with the idea to maneuver the knight ...Nc8–e7–f5 to strike at the weak d4-pawn.

In either case, White obtains attacking chances, and so Taylor recommends 5...d5 followed by 6...e6 to reach a position akin to the French Defence.

Unlike the Four Pawns Attack, the white centre is not as fluid and the game takes on a more strategic character.

The resulting pawn structure leads to position similar to that of the Winawer Variation of the French Defence.

[9] If Black does not want to defend against White's attacking opportunities against 3...Nxc3 4.dxc3, then 3...e6 is a reasonable alternative that was Alekhine's choice when meeting the Two Knights, and this defence has been advocated by Taylor.

Another rare line, but one that scores well in practice is 3.d4 d6 4.Be2, preventing Black from playing 4...Bg4 while retaining the option of making the pawn advance f2–f4.

White's main continuation is to deploy the queen rook for duties on the kingside with 5.Ra3, followed by Rg3 at some point when the attack on g7 is supposed to tie Black down from developing the bishop to e7.

[9] The idea for this unusual early "rook lift" probably originated with the well-known American International Master Emory Tate.

2.Nc3 is by far White's most common alternative to 2.e5; in fact Cox noted that he saw this move in over half his games with the Alekhine.