will try to drive Black's advanced knight from e4 with moves like c4 and Re1. If White achieves this, then he is up two tempi (Nf6–e4–f6, plus the tempo White starts the game with). In practice White is usually able to achieve this, but at some structural cost such as having to play c4, which balances out. White can also force simplification with Lasker's 5.Qe2 Qe7 6.d3. This is generally only good enough for a draw, which Black should be satisfied with. Another possibility, explored by Keres, is 5.c4, known as the Kauffmann Attack. A completely different approach is to meet 4...Nxe4 with 5.Nc3 Nxc3 6.dxc3 with rapid and castling. For instance, White can plan a quick Be3, Qd2, and 0-0-0, and play for a attack, trusting that his doubled c-pawns will help protect his king, and that his initiative and attacking potential will offset the longterm disadvantage of having doubled pawns. In the 5.Nc3 line, Black must avoid 5...Bf5?? 6.Qe2! which wins a piece due to the pin (if 6...Qe7 7.Nd5, forcing 7...Qd7 because of the threat to the c7-pawn; then 8.d3 wins the piece). Viswanathan Anand resigned after only six moves after falling for this against Alonso Zapata at Biel in 1988. The Cochrane Gambit, 4.Nxf7, is labelled "speculative but entertaining" by Nick de Firmian in Modern Chess Openings (MCO) 14th edition. He evaluates the position in Veselin Topalov–Vladimir Kramnik, Linares 1999 as offering chances for both sides after 4...Kxf7 5.Nc3 c5!? 6.Bc4+ Be6 7.Bxe6+ Kxe6 8.d4 Kf7 9.dxc5 Nc6. The Paulsen Variation, 4.Nc4, is labelled "ineffective" by de Firmian in MCO, but is occasionally seen at grandmaster level. US master Andrew Karklins has experimented with 4.Nd3!?, now called the Karklins–Martinovsky Variation. This was played in the World Chess Championship 2018 between Magnus Carlsen and Fabiano Caruana. The Stafford Gambit, 1.e4 e5 2.Nf3 Nf6 3.Nxe5 Nc6, is considered dubious, but it sets a few traps. After 4.Nxc6 dxc6, White wins a pawn but must play carefully. After 5.e5 (5.d3 is better) Ne4 6.d3?? (White should play 6.Nc3, 6.d4, or 6.Qe2) 6...Bc5! and White resigned in Lowens-Stafford, US correspondence game 1950. Steinitz Variation: 3.d4 3.d4 was favoured by Wilhelm Steinitz, and is sometimes called the Steinitz Variation, although it was known earlier. Black can capture either pawn; also possible is 3...d6, transposing into the Philidor Defence. After 3...exd4 4.e5 (4.Bc4 transposes into the Urusov Gambit) 4...Ne4 (4...Qe7?! 5.Be2 is