needs to consider whether or not to deal with the positional threat of ...b5. The old main line 7.Qe2 allows ...b5, and theory holds that Black can equalise against it. The main modern preference is the retreat 7.Bb3, so that 7...b5 can be met with 8.a4, while 7.a4, stopping ...b5 at the cost of weakening the b4-square, is also popular, and was played by Mikhail Botvinnik in his 1963 match with Tigran Petrosian. 7.dxc5 leads to an early queen exchange, and often to an early draw. Rarer lines which have been played are 7.e4 (Geller), 7.Nc3, 7.Nbd2, 7.a3, 7.b3, and 7.Bd3. 3...a6 This is the Alekhine Variation. White usually continues 4.e3. 4...Nf6 tends to return to the main line. This is an uncommon line that mainly focuses on rapid development of pieces along with domination of the centre. This variation was debuted by Alexander Alekhine against Efim Bogoljubov in 1929. 3.e4 White can try to establish a strong pawn centre with 3.e4, an old move that became popular again in the 1990s. Rizzitano calls it the Central Variation and notes its increase in popularity and strategic and tactical complexity. Raetsky and Chetverik consider the line straightforward and critical, and remark that anyone playing the Queen's Gambit Accepted must be prepared to meet it. Trying to protect the pawn with 3...b5 is fairly risky and rarely seen. The main reply against the Central Variation is to oppose the pawn centre with 3...e5, which is a highly theoretical system. Other replies aimed at challenging the centre are 3...Nc6 with ideas akin to the Chigorin Defense, 3...Nf6, provoking 4.e5, and 3...c5 undermining the centre at d4. 3.e3 The apparently modest 3.e3 prepares immediate recovery of the pawn and has often been employed by strong players, including Anatoly Karpov. The line long had a harmless reputation due to the early discovery of 3...e5 which strikes back at the centre. A typical continuation is then 4.Bxc4 exd4 5.exd4, leading to an isolated queen's pawn position. However, the open positions which ensue have not proved easy for Black to handle in practice, and many players simply play 3...e6 to transpose back to the main lines. Nonetheless, 3...e5 was Rizzitano's recommendation in his repertoire against 3.e3. An opening trap where Black tries clinging onto the c4-pawn was pointed out by Alessandro Salvio in 1604. If Black defends the pawn with 3...b5? 4.a4 c6 5.axb5 cxb5??, the a8–h1