- 1.e4 e5 2.a3
- 1.e4 e5 2.Nc3 Nf6 3.a3
- 1.e4 e5 2.Nf3 Nc6 3.Nc3 Nf6 4.a3
Against each of these move-orders Black can resolutely turn the table back again with the reply ...a6. Instinctively one would think that these extra moves - which mainly appears to have defensive qualities - would favor Black who by nature is the defending part. However it's not that clear in practice. Actually it turns out to be quite hard to figure out how the extra moves influence the resulting double king-pawn positions:
1.e4 e5 2.a3 a6 (Dia)
a) Sadly 3.f4!? with a Pseudo King's Gambit seems untested.
b) 3.Nc3 Nf6 4.Nf3 would transpose but the Vienna style moves 4.Bc4 or 4.f4!? may be worth a try.
c) 3.d4 exd4 4.Qxd4 Nc6 5.Qe3 d6 looks like a slight improvement over the well-known 2.d4 exd4 3.Qxd4 Nc6 4.Qe3 line of the Centre Game. However, in Hofstetter-S.Mueller, Kahl 1996 chances were equal after 6.Nc3 Nf6 7.Bd2 Be7 8.Bc4 Be6 9.Nd5 0–0 10.Ne2 Ne5 11.Nxf6+ Bxf6 12.Bxe6 fxe6.
a) 4.Bc4 b5 5.Ba2 Nf6 6.Ng5 d5 7.exd5 Nxd5 8.Nxf7 Kxf7 9.Qf3+ Ke6 10.Nc3 Nce7 11.d4 Qd6? (11...Bb7) and in Vasic-Ristovski, Portoroz 2003 White could have obtained a winning position with 12.Ne4.
b) 4.d4 exd4 and now:
b1) I really don't understand why nobody has tried 5.Nxd4 Nf6 6.Nxc6 bxc6 7.e5. In this line it's quite likely that Black's ...a6 will be to his disadvantage, as he after 7...Qe7 8.Qe2 doesn't have the sharp option ...Ba6.
b2) 5.c3 dxc3 6.Bc4 d6 7.0–0 Bg4 8.Qb3 Qd7 9.Ng5 (after 9.Bxf7+ Qxf7 10.Qxb7 Kd7 11.Qxa8 Bxf3 12.gxf3 Qxf3 Black at least has a perpetual check) 9...Bh5 10.Bxf7+ Bxf7 11.Nxf7 Na5 12.Qxc3 Qxf7 13.Qxa5 and White had a clear advantage in Zagrapan-Ilkovics, Slovakia 1998.
One of the strengths as well as the limitations of the Three Knights Opening is the fact that it reduces the active options for both sides. With a3 and a6 eliminating all lines with Bb5 and ...Bb4 this becomes even more pronounced. 4...Bc5?! is met strongly by 5.Nxe5!
5.g3 Nxe4?! is yet another version of the Halloween Gambit. I cannot even guess if the extra a-pawn moves favor any of the sides but a sensible solution is as usual to return the piece with 6.Nxe4 d5 7.Nc3 d4 8.Bg2 dxc3 9.bxc3 which would be a well-known theoretical position if it weren't for these extra a-pawn moves. But maybe the entire gambit is silly as Black after 8.Ne2 the doesn't have option of ...d3 followed by ...Nb4.
5...exd4 6.Nxd4 (Dia)
a) 6...Nxd4 7.Qxd4 simply gives White the freer game and slightly the better chances, e.g: 7...d6 8.Be2 Be7 9.0–0 0–0 10.Bf4 Be6 11.Rad1 += Bucher-Knaus, Switzerland 2006.
b) 6...g6 7.Bg5 (7.Nxc6 bxc6 8.e5 Qe7 9.Qe2 Nd5 10.Ne4 Bg7 11.c4 +=) 7...h6 8.Bh4 Bg7?? (8...d6 9.Bxf6!? Qxf6 10.Nd5 Qxd4 11.Nxc7+ Kd8 12.Nxa8 Qxe4+ 13.Qe2) 9.Nxc6 bxc6 10.e5+- Gunsberg-Zukertort, London 1887.
c) 6...d6 7.f3 (7.Nxc6 bxc6 8.Bc4 Be7 9.0–0 +=) 7...g6 8.Be3 Bg7 9.Qd2 Qe7 10.0–0–0 Be6 11.g4 += Nanu-Chirpii, Eforie Nord 1999.
d) 6...d5 7.exd5 Nxd5 8.Nxc6 bxc6 9.Bc4 Qe7+ 10.Ne2 Qe4 11.Bxd5 Qxd5 (11...cxd5 12.0–0 +=) 12.0–0 Bd6 13.Bf4 += Bhend-Mottas, Pizol 1997.
a) After 7.Nb3 Ba7 only Black has any use of the extra a-pawn moves.
b) 7.Be3 may well be best.
b1) Instinctively 7...Bb6 looks less compact with the pawn on a6.
b2) After 7...Ba7 8.Nxc6 bxc6 9.Bxa7 Rxa7 Black's rook looks a little silly.
b3) 7...Nxd4 8.Bxd4 looks more comfortable for White: 8...Qe7 (after 8...Bxd4 9.Qxd4 d6 10.0–0–0 0–0 11.e5 Ng4 12.f4 Qh4 13.exd6 cxd6 14.g3 Qh5 15.h3 White was clearly better in Eichner-Feldmann, Germany 2006) 9.Be2 d6 10.Bxc5 dxc5 11.0–0 0–0 12.Qd3 += Pirttimaki-Nippula, Finland 1993.
This must be better than 8.Bc4 d6 9.h3 h6 10.0–0 0–0 = of E.Reppen-Garcia Serrano, Copenhagen 2004.
8...Qe7 9.Qe2 Nd5 10.Ne4 (Dia)
10...Bd4!? 11.f4 f5 12.c3 Ba7 is better and at first glance unclear.
11.c4 Nb6 12.Bg5
White's opening has been a success - White is at least somewhat better, Braeuning-X.Garcia, Barcelona 1997.