pawn with 5.fxe4 Nxe4 6.Qf3, when both 6...Nxc3 and 6...Nd6 lead to complicated positions in which Black often tries to return a pawn on b7 in order to catch up on development, and in some cases secure a positional advantage. White often does best to continue with a gambit policy and simply continue developing. The main line runs 6...Nd6 7.Bf4 e6 8.0-0-0 c6 9.g4 Bg6 10.Qe3 Be7, when Black is solid, but White retains enough compensation for the pawn. Alternatively, 5.g4 aims to regain the pawn in most cases, e.g. after 5...Bg6 6.g5 Nd5 7.Nxe4 Nc6 8.Bb5 e6 9.Bxc6+ bxc6 10.Ne2 c5 11.dxc5 Nb4, when in a reversal of roles, White has an extra pawn but Black has the initiative and a superior pawn structure. White can use 5.g4 as a gambit option by continuing with 6.h4!?, which leads to sharp play and approximately equal chances. Langeheinicke Defence: 4...e3 The push with 4...e3 is often used by strong players to avoid the complications arising from 4...exf3 5.Nxf3, but it is one of Black's weaker options against the Blackmar–Diemer as returning the pawn in this way does not significantly slow down White's initiative, and thus Black struggles to fully equalize in this line. In most lines White must seek to place a knight on f4 (taking the sting out of ...Nd5) in order to secure an advantage. Third-move alternatives for Black Lemberger Counter-Gambit: 3...e5 The Lemberger Counter-Gambit is an important alternative, where Black counterattacks against the d4-pawn instead of defending the attacked e4-pawn. White can head for a drawish endgame with 4.dxe5, e.g. 4...Qxd1+ 5.Kxd1 Nc6 6.Nxe4 Nxe5, or 5.Nxd1 Nc6 6.Bf4, with equality and few winning chances for either side. Since these positions typically do not attract gambiteers, White often chooses a riskier response in order to generate winning chances, such as 4.Qh5, 4.Nge2 or 4.Nxe4. Both 4.Qh5 and 4.Nge2 are well met by 4...Nc6!, when Black has good chances of obtaining an advantage, while against 4.Nxe4 the most critical continuation is 4...Qxd4, when White can continue with either 5.Qe2 or 5.Bd3, with complications and some compensation for the pawn in either case, but it is unclear if it is enough. Other options for Black 3...f5 is an important option for Black, since 4.f3 is well met by 4...e5!, with some advantage for Black. Instead White does better to prevent ...e5 with 4.Bf4, and then obtain compensation for a pawn