Round 1

The Potter Variation with 5.Nb3 is not an attacking system, it is a space system. White keeps the centre, develops with 7.Bf4 and 8.Qd2 towards the long castle, and after 9.O-O-O O-O the kings sit on opposite wings. From there every tempo counts twice, because both sides want to march pawns at the other king.

11.Bg5 provokes 11...f6, and after that the bishop has exactly one good square. It is 12.Be3: after 12.Bf4 Nxf4 13.Qxf4 the bishop leaves the board and the whole advantage goes with it, and 12.Bh6 gxh6 is far worse still. On e3 the bishop stands behind its own pawns and opposite the black bishop on b6, and Black released the tension himself with 13.exf5 Bxe3 14.Qxe3, which put the white queen on her best square.

I would have played 11.Be3 at once and skipped the detour to g5; the difference is about a fifth of a pawn, so a matter of taste. The lesson holds for any game: when a piece has to move, first ask which square survives being attacked with tempo, and only then which one looks most active.

Two thirds of all players would play 19.Nd4 here and trade: 19.Nd4 Nxd4 20.Qxd4 Nc6 21.Qd5+ Be6 looks sensible, the a4 pawn is dealt with, the queen is central. White is still better afterwards, but only about half as much as before.

19.Nc1 looks backward and is not. The knight stays on the board, comes back into play via e2 or d3, and White keeps exactly the pieces Black would like to swap off. Manko followed with 21.a3, which takes the a3 square away from the pawn on a4, and when 21...Na5 attacked the bishop on c4, 22.Ba2 stepped aside and kept the a2-g8 diagonal.

Not every exchange is progress. The attacker needs pieces, the defender wants to be rid of every single one of them. The question before a trade is not whether it looks good, but whose position is more cramped afterwards.

After 26 moves White had everything the opening promised: a safe king, the f4 and g4 pawns advancing, the black knight stranded on a5 and an advantage worth roughly two pawns. What the position asks for now is a move that improves a piece and threatens something at the same time.

That move was 27.Rd4. The rook attacks the bishop on e4, and after 27.Rd4 Bg2 28.Rxe8+ Qxe8 29.Qxc7 White has won a pawn and kept the queens on. The game went 27.Ne2, which improves a passive piece and does nothing else. 27...Qc6 offered the queen trade at once, 28.Qxc6 Nxc6 accepted it, and barely a third of the advantage survived.

This is the most expensive kind of move there is, because it does not look like a mistake. When you are clearly better, every piece improvement deserves a second question: is there one that also threatens something? An advantage that threatens nothing gets traded off sooner or later.

From move 36 both players had under a minute left before the time control, and the game became what such games become. The most important move of that phase was 40.Kc1. The square a2 is the only one in that corner where a knight on b3 can never give check, and 40.Ka2 would have put the king exactly there. 40.Kc1 chose the other square, and nine moves later a black knight landed on b3 with check.

In between, the h6 pawn simply stayed on the board. 41.gxh6 was clearly stronger than the 41.f5 that was played, and after 42.gxh6 gxh6 the calculation was straightforward: 43.Rxh6+ Kg7 44.Rh4 Nf3 45.f6+ Kf7 and the passed pawn keeps running with check while the black king has no cover left. The game went 43.Rff1, and only a remnant of the advantage was left.

For your own time trouble there is an order of business that almost always works: first every check, then every capture, then everything else. 43.Rxh6+ is both at once, a capture with check, and it sat at the top of a list nobody had time to read.

A knight check cannot be blocked, and the knight on b3 is attacked by exactly one piece, the pawn on c2. That leaves 49.Kb1, 49.Kd1 and 49.cxb3, and two of the three lose the game.

49.Kb1 Rg1+ 50.Bf1 Rxf1+ 51.Ka2 Ra1# is mate in three. 49.Kd1 Rxd3+ drops the bishop with check and leaves White lost. With under two minutes on her clock Manko played the third move, 49.cxb3, which tears open her own king position and wins precisely because of it: 49.cxb3 Rxd3 50.Rg7+ Kf8 51.bxa4 and White has two passed pawns, on a4 and on f6.

Fourteen accurate moves followed in a row. 51.bxa4 c5 52.Rxb7 Rd4 53.a5 sets the pawn going, the rook on b5 clears its path, and 61.a8=Q+ Kf7 62.Qd5+ ended the game. The lesson from move 49 is the plainest one in chess and the most often forgotten: when you are in check, list every legal answer first, then judge them. Three moves take ten seconds to list. Step aside with the king by reflex, because that is what one does, and you lose this position.