Wall, Bill - Guest6953174
1.e4 e5 2 Nf3 Nc6 3.Bc4 Bc5 4.Bxf7+
4...Kxf7 5.Nxe5+ Nxe5 6.d4 Bb4+
The "tool" stays in the toolbox. The wildest move here is the "pie-in-the-face" 6...Qh4!?. True, Black's Queen loves to come to e7 or f6, but there are times when this move is critical.
The Database has 1,459 games with 6.d4, but only 223 times (15%) is it answered by 6...Qh4. Admittedly, the move makes the same "mistake" as White's early Queen development, so it is probably not on Black's mind.
It takes a search depth of 23 ply for Stockfish 7 to settle on 6...Qh4, so it is not the first thing to come to the computer's "mind" either.
Sometimes Black just leaves the Bishop on b4. See "Further Exploration of An Odd Line".
Bill has seen several responses:
7...Nc4 8.cxb4 Qf6 9.Nc3 c6 10.b3 Qg6 11.Qf3+ Nf6 12.bxc4 Re8 13.O-O Kg8 14.e5 Ng4 15.h3 d6 16.hxg4 Bxg4 17.Qg3 Rf8 18.exd6 Black resigned, Wall,B - Anonymous, lichess.org, 2016;
7...Qe7 8.dxe5 Bc5 9.Qd5+ Ke8 10.O-O c6 11.Qd1 d6 12.b4 Bb6 13.exd6 Qe5 14.Bb2 Nf6 15.Nd2 Be6 16.Nf3 Qf4 17.Bc1 Qg4 18.Re1 Nxe4 19.Be3 Rf8 20.Bxb6 axb6 21.Qd4 Rf4 22.h3 Qg6 23.Ne5 Qf5 24.Nd3 Rh4 25.Qxg7 Qf7 26.Qd4 Rd8 27.Rxe4 Rxe4 28.Qxe4 Rxd6 29.Re1 Kf8 30.Ne5 Qf5 31.Qe3 Bxa2 32.Qxb6 Rd2 33.Qe3 Rd6 34.Qc5 Qe6 35.Re3 Qh6 36.Nd7+ Kg8 37.Qe5 Rd1+ 38.Kh2 Rxd7 39.Qe8+ Qf8 40.Qxd7 Bf7 41.Qxb7 Qd6+ 42.g3 Kf8 43.Rf3 Qe6 44.Qxf7+ Qxf7 45.Rxf7+ Kxf7 46.c4 Ke6 47.b5 Kd7 48.f4 Kd6 49.b6 c5 50.f5 Black resigned, Wall,B - Guest3742987, PlayChess.com, 2015;
7...Bxc3+ 8.Nxc3 Ng6 (8...Nc6 9.d5 [9.O-O Qf6 10.e5 Qg6 11.Qf3+ Ke8 12.Nb5 Kd8 13.Qf8+ Qe8 14.Qxe8+ Kxe8 15.Nxc7+ Ke7 16.Nxa8 Nxd4 17.Bg5+ Ke6 18.Nc7+ Kxe5 19.Rae1+ Kd6 20.Bf4+ Kc6 21.Rc1+ Kb6 22.Nd5+ Kb5 23.Rxc8 Ne6 24.a4+ Kxa4 25.Ra1+ Kb3 26.Be5 Black resigned, Wall,B - Caynaboos, FICS, 2011] 9...Ne5 10.f4 Ng6 11.h4 Nxh4 12.Qh5+ g6 13.Qxh4 Qxh4+ 14.Rxh4 Nf6 15.e5 Ne8 16.Be3 c6 17.O-O-O d6 18.e6+ Ke7 19.g4 Nf6 20.f5 gxf5 21.gxf5 cxd5 22.Bg5 a6 23.Nxd5+ Kf8 24.Bxf6 Rg8 25.Rxh7 b5 26.Be7+ Ke8 27.Nf6 checkmate, Wall,B - ChessFlower, PlayChess.com, 2012) 9.O-O Nf6 10.e5 Ne8 11.f4 (11.Qf3+ Kg8 12.Qd5+ Kf8 13.Be3 a6 14.Rae1 c6 15.Qb3 d5 16.f4 Kg8 17.f5 Nh4 18.Qc2 g6 19.f6 Be6 20.Bg5 Qb6 21.Bxh4 Qxd4+ 22.Bf2 Qf4 23.Ne2 Qc4 24.Qd2 Qxa2 25.Nd4 Bf5 26.Nxf5 gxf5 27.Qg5+ Kf7 28.e6+ Kf8 29.Bc5+ Nd6 30.Bxd6+ Ke8 31.f7 checkmate, Wall,B - Boris, Sparkchess.com, 2012) 11...Rf8 12.f5 Ne7 13.Qb3+ d5 14.exd6+ Black resigned, Wall,B - FJBS, FICS, 2015; and
7...Be7 8. dxe5 Nh6 9. Qf3+ Ke6 10. Bxh6 gxh6 11. Qf5 checkmate, Wall,B - ChrSav, FICS, 2010.
Once again, the "tool" stayed in the toolbox. As an alternative, Black had 7...Qh4!?, which was seen 10 times in The Database, with 10 wins for Black. It is slightly less mysterious: Stockfish 7 takes only 15 ply to find the move.
There was reason to admit that move 7 was a mistake, and to try 8...Be7.
9.Qd5+ Kf6 10.f4 Kg6 11.O-O Bf6
This allows mate.
12.f5+ Kh5 13.Qd1+ Kh4 14.Rf4+ Kg5 15.Rf3+ Black resigned