1.d4 Nf6 2.Nf3 g6 3.c4 Bg7 4.Nc3 0-0 5.e4 d6 6.Be2 e5 7.d5 a5 8.Bg5 h6 9.Bh4 Na6 10.Nd2 For those who are interested in these things, there are three games on my database in which Mark Hebden has reached this position, all 25 years plus ago, and he won the lot.
10...Qe8 In the second Rossiter game he played the text move. [He played Philip Rossiter twice from this position, and in the first he played 10...h5 11.Bg5 Qe8 ]
11.0-0 [In the first game, Rossiter castled queenside, but in the second he decided to play on the queenside and started 11.Rb1 Bd7 12.b3 Nh7 13.f3 h5 14.a3 waiting until move 28 before castling kingside!]
11...Nh7 12.a3 Bd7 13.b3 h5 14.f3 Bh6 15.Qc2 [In the first game of Mark's on my database, John Cooper also chose to play on the queenside with 15.Rb1 but he eventually succumbed to a vicious kingside attack.]
15...Nc5 16.Rab1 Be3+ 17.Bf2 Bxf2+ 18.Rxf2 Qe7 19.b4 Na6 20.Bd3 Nf6 21.Nf1 Rfb8 A Grandmasterly piece of prophylaxis. White has in reserve the capture bxa5, which opens an attack on the pawn at b7. [21...Rab8 allows 22.bxa5 (or 22.Na4 Bxa4 23.Qxa4 axb4 24.axb4 ) ; and he is able to keep the tension on the queenside by avoiding 21...axb4 22.axb4 ]
22.b5 [22.bxa5 is met by 22...Nc5 which gives Black the edge on the queenside. So White decides to close the position there.]
22...Nc5 23.Na4 Nxa4 24.Qxa4 h4! A thematic advance. Black strengthens his grip on the kingside dark squares.
25.Qc2 b6 26.Qd2 Kg7 27.f4?! White fears the gradual build-up of pressure against his kingside, but hands the e5 square to the black pieces.
27...Ng4 28.Re2 exf4 29.Qxf4 Qe5 30.Qxe5+ Nxe5 31.Rb3 h3! Well timed. [31...h3 Now 32.g3 loses the exchange to 32...Nf3+ 33.Kf2 Nd4 so White must allow the isolation of his h-pawn.]
32.Rc3 hxg2 33.Kxg2 Rh8 34.Ng3 Bh3+ 35.Kh1 Rh4 White has a lot of weak or vulnerable pawns. The h-pawn is isolated, the e-pawn is back ward on an open file and the c- and a-pawns are vulnerable (the last from an attack from behind once it gets to a4) . The bad bishop can defend three of them, but Hebden is able to resrict it to the e2 square which helps him to put White in Zugswang.
36.Rf2 Rah8 37.Be2 Bg4 38.Nf1 Rh3 Removing one defender of the c4 pawn.
39.Rxh3 Bxh3 40.Ng3 Kf8 41.Kg1 Ke7 42.Rf4 Rh7 43.Kh1 g5 44.Rf2 Rh4 45.Kg1 Rf4! 46.a4 [46.Rxf4 gxf4 47.Nh5 (47.Nf1 f3 ) 47...f3 48.Bf1 Bxf1 removes the other defender of the c4 pawn.]
47.Nh5 [47.Nf1 Bxf1 48.Kxf1 Rh6 49.Kg2 Rh4 50.Bf3 Rf4 and the e4 pawn goes.; 47.Nh1 Bg4 48.Bxg4 Nxg4 49.Rc2 Rf3 and the a4 pawn will soon go.]
47...Rxf2 48.Kxf2 Bg4! 49.Bxg4 Nxg4+ 50.Kf3 [50.Kg3 Ne5 wins the c4 pawn, but losing the h2 pawn is no better.]
50...Nxh2+ 51.Ke3 Ng4+ 52.Kd4 Ne5 53.Ng3 Nd7 54.Nf5+ Kf6 55.Kc3 0-1