Black’s queen bishop lacks a good square. He equalized with the bishop tour, 1 …Bg4+! 2 f3 Bh5 and … Bg6.

Play went 3 h4 0-0 4 g4 Bg6. Then on 5 Bxg6, the irregular recapture, 5 … fxg6! followed by … Rae8 is best. This favors Black because of his play along the e- and f-files.

White has greater winning chances with a knight shift, 1 g4! Bg6 2 Nh4!. After 2 …Nc6 he was careful to avoid 3.Nxg6? because this is another case when 3 … fxg6! helps Black.

White’s superiority was clear after 3.Nhf5! Qd8 4 Qf3 Ne8 5 h4! Bxf5 6 exf5! Rc8 7 g5 and he eventually won.

The best move is 1 … b4 so that a White knight move allows 2 … Nd5!.

But here it turns out disastrously, 1...Bxf3? 2.gxf3 2 … b4?? 2 exf6 bxc3 3 Rg2!, since 3 … Bxf6 4 Qxf6 is hopeless.

The game ended with 3 … Qb7 4.Rxg7+ Kh8 5 Rg8+! resigns

(5 … Kxg8 6 Rg1+ Kh8 7 fxe7+ or 5 … Rxg8 6 fxe7+ Rg7 7 Rg1).

If you relied on calculation, you might start with 1 … Nh7. That threatens … Bxh4 and might lead to 2 g5 hxg5 3 hxg5 e5.
But White can make a promising sacrifice with the endangered g-pawn. 4 g6! fxg6 5 Bg4 and Nd5.
It’s better to rely on an anti-g4 and look at 1 … d5!.

The game ended in a draw after 4 cxd5 Rxc3 5 Bd4! Rxa3 6 g5 hxg5 7 hxg5 e5! 8 fxe5 Qxg5+.

The c-file is closed half-way but 1...Na5! prepares the Philidor Ring.

After 2 Nhf1 b5 White faced the prospect of 3 … b4.

White stopped the b-pawn’s advance with 3 a3. The drawback is 3 … Nc4!.

That forced an exchange of pieces because both 4 …Nxb2 and 4 …N xd2 were threatened. After 4.Nxc4 bxc4:

Because of 3 a3 White cannot play b2-b3 or b2-b4 without losing at least one pawn. This meant Black was free to pile up against b2 with his rooks, 5 Ne3 Ra6! 6 g3 Rb6 7 Ra2 Ra8 8 Bf3 Ra5! 9 Kg2 Rab5. He eventually won.