An important hint, thank you very much! I overlooked the transposition, although 7.Bd2 Bxd2+ 8.Nbxd2 Nxe4 was prominently played by Fischer, Rubinstein, Rotlewi, Honfi and others (87 games are in the database). The "full" transposition 12.0-0 was reached in 2 of these games, both drawn. The very similar situation after 11...cxd6, when White can also try 12.0-0-0 or 12.Qxd6, also showed a level score of 4.5 out of 9 games.
A few remarks on this different move-order:
1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. c3 Nf6 5. d4 exd4 6. cxd4 Bb4+ 7.Bd2 Bxd2+ 8.Nbxd2 Nxe4 9.d5 Recommended by Ritzen (1924), Pinski (2005) still regards the text move as the main line: "8...Nxe4 looks tempting, but White reacts energetically with 9.d5! ..."
While 9.Bxf7+? (a long time ago it was given a ! in the Bilguer) 9...Kxf7 10.Nxe4 Re8 is incorrect, e.g. 11.0-0 Rxe4 12.d5 Ne5 13.d6 Kf8!, other alternatives are playable:
(a) 9.Nxe4 d5 10.Bd3 dxe4 11.Bxe4 0-0 12.0-0 Bg4 13.Bxc6 bxc6 [=, 41] Leonhardt - Rotlewi, Hamburg 1911; 14.b3 with a slight plus, but it should still become a draw.
(b) 9.Qe2 d5 10.Nxe4 0-0 11.0-0-0 Bg4 12.h3 Bxf3 13.gxf3 dxc4 (dxe4) 14.Qxc4 Qh4 and Black was somewhat better in Mednis - Fischer, New York 1963.
9...Nxd2 10.Qxd2 10.Kxd2!? Ne7 11.Ng5 is interesting, but after 11...d6 12.Qh5 g6 13.Qh4 h5 14.Ne4 Ng8 15.Bb5+ Bd7 16.Bxd7+ Qxd7 White is lacking a strong continuation: 17.Rhe1 (or perhaps 17.Nf6+ Nxf6 18.Rhe1+ Kf8 19.Qxf6 Rh7 =+; 17.Rac1 Kf8 18.Qh3!? Qa4 19.Qd3 Nf6! 20.Nxf6 Qf4+ etc.) 17...Kf8 18.Rac1 Rc8 19.Rc4 (19.Qf4 Qa4 20.b3 Qxa2+ 21.Kc3 b5) 19...Qb5 20.Nc3 Qxb2+ 21.Kd3 Qb6 22.Rb1 (22.Qh3 Rd8) 22...Qa6 23.Qd4 Rh7 24.Nb5 f5 25.a4, and White may have sufficient compensation, but not more.
10...Ne7 10...Nb8? 11.d6 0-0 12.Rc1 Nc6 13.dxc7 Qxc7 14.0-0 Qa5 15.Qd6 Qb4 16.Bxf7+ Rxf7 17.Rxc6 Qxb2 18.Re1 Qf6 19.Qd5 1-0, Traxler - Duras,
Wiener Schachzeitung 1915, p. 208.
11.d6 cxd6 12.0-0 If 12.Qxd6, the reply 12...0-0 is probably best. (12...b5 Tzermiadianos - Kotronias, Athens 1998, seems slightly better for White) 13.0-0 (White might try 13.00-0 Nf5 14.Qf4 d6!? [or 14...Ne7 15.Bd5 Nxd5 16.Rxd5 d6 17.Qxd6 draw, Engelbert - Budzyn, Kiel Open 2006] 15.g4, but both 15...Ne7 and 15...Nh6 seem to be acceptable for Black) 13...Nf5, about =.
12...0-0. 12...d5 13.Bxd5 0-0 14.Rfe1 d6 and soon a draw was agreed in Berlinsky - Estrada Nieto, Istanbul 2001.
13.Qxd6 Nf5 14.Qf4 d5 15.Rad1 Ne7 16.Rfe1 h6 17.Qe3 Be6 18.Nd4 Bg4! 19.Be2 Bxe2 20.Rxe2 Re8 =+, Satici (2354) - Cerqueira Filho (2428), Dr. Maia Vinagre Memorial 2007. The game later ended in a draw. - Instead of 13.Qxd6, the cautious 13.b3 may be more precise, to avoid later attacks on the weak pawn b2, e. g. 13...d5 14.Bxd5 Nxd5 15.Qxd5 d6 16.Rad1 Qb6 and so on; the position is equal.
Quote:So, that line is both important for White for the 7.Nbd2 line but also for 7.Bd2.
I agree.