U.Andersson - M.Basman,
This is known as the English Opening. The talented English IM, Basman probably never quite realized his full potential. Whether it was due to his penchant for unorthodox openings or not is hard to say - his provocative style certainly earned him quite a few points too.
Andersson makes no attempt to refute Black's opening which in 1974 must have seemed a lot more unorthodox than it does today.
2...Bb7 3.Bg2 e6 4.0–0 d5 5.c4
Swedish grandmaster Ulf Andersson was known for his defensive technique, his risk avoidance and his faith in healthy if passive positions. He combined this playing style with a unique endgame understanding and a formidable willingness to play on forever in seemingly dead drawn endgames - frequently extracting that extra half point in the end.
5...Nf6 6.d4 Be7 7.Nc3 0–0 8.Ne5 h6 9.Bf4 a6 10.Rc1 Ra7 11.cxd5 exd5 12.Qb3 (Dia)
White has gained a fairly clear and stable advantage from the opening. Black is solid but he will find it hard to create counter-play. What happens now is an interesting case of psychological warfare. Basman abandons all attempts to free his position and just waits for the attack.
12...Ba8 13.Rfd1 Kh7 14.h3 Kg8 15.Kh2 Kh7 16.g4
This is a move you rarely see Andersson play in the opening or middlegame. Psychologically this may be the root to his eventual defeat .
16...Kg8 17.Bg3 Bb7 18.e3 Ba8 19.a3 Bb7 20.f4
Andersson's kingside pawns are lured forward. Probably the old Steinitz saying that the player with an advantage is obliged to attack were whispering somewhere in the back of his mind.
20...Ba8 21.Rd2 Qd6 22.f5 Qd8 23.Bf4 Bb7 (Dia)
Remarkably nothing has changed in Black's position since the last diagram. White's attacking pawn cloud looks imposing but actually his strategy may be mistaken.
24.Rg1 c6 25.Bf3 Nh7 26.Rc1 Bd6 27.Na4 Bc7 28.Kg3 Nf6 29.h4 Nfd7
Almost imperceptibly the game has turned. White has accepted too many obligations and is now actually struggling to defend his territory.
30.Nxd7 Nxd7 (Dia)
31.Re2 Re8 32.Kh3 Bxf4 33.exf4 Rxe2 34.Bxe2 Qe7 35.Bf3 b5 36.Nc5 Bc8 37.Qd3 h5 38.gxh5?!
38.g5 seems to keep White’s position more compact and would probably have been stronger.
38...Qf6 39.Kg3 Nxc5 40.Rxc5 Bxf5 41.Qc3 Bd7 42.Qd3 Ra8 43.Rc1 Re8
Black may be winning already thanks to White's weakened king's position.
44.Qc3 c5 45.Qxc5?
White had to try 45.dxc5. However, after 45...d4 46.Qd2 Re3 47.Re1 Rxe1 48.Qxe1 Qf5 49.Qe4 Qxc5 50.Qe5 Qc4 Black's passed d-pawn gives him a very clear advantage.
Now all Black's remaining pieces take part in the attack - there just is no defence.
46.Qxd5 Qh3+ 47.Kf2 Qh2+ 48.Bg2
48.Kf1 Bh3+ is even worse.
48...Qxf4+ 49.Bf3 Bg4 50.Rc3 Qh2+ 51.Bg2 Qxh4+ 52.Kg1 Re1+ 53.Bf1 Bh3
(With 54.Rxh3 Qxh3 55.Qa8+ Kh7 56.Qe4+ Rxe4 57.Bxh3 Rxd4 White only reaches a completely lost endgame.)