Ruy Lopez Open Defence 
White is once again threatening to win Blacks e-pawn, although Black is temporarily a pawn up anyway. More importantly, Black needs to complete her development and if possible reinforce the crusading knight on e4, but the immediate ...d5 would leave the c6-knight pinned allowing the powerful Nxe5. 6...Be7 is a semi-useful move, but to really get to grips with the situation Black should play 6...b5 preparing ...d5 by chasing the bishop away.
Black can also accept White's gambit with 6...exd4, which leads to a wonderful mess.
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