Pim O'Clock

THE annual Pimlico Summer congress, held over five consecutive Thursdays, began last night with a full complement of 64 entries.
It is split into three sections - open, U150 and U120 - with a time limit of 75 minutes plus a 15-second increment.
Combined with a 6.30pm start, this means the vast majority of games are over before 9pm.
Paul Carlucci (154) - Spanton (171)
Colle-Zukertort
1.d4 d5 2.Nf3 Nc6
The fourth-most popular move in ChessBase's 2019 Mega database, and the worst-scoring percentage-wise among the top 10 replies. Nevertheless it has been tried by strong players including Carlsen and Rapport.
3.e3
The Colle route. More popular these days is the London System with 3.Bf4, while 3.c4 transposes into a mainline of the Chigorin.
3...Bg4 4.Be2 Nf6
Rapport and Morozevich have preferred 4...e6, which was played all the way back in 1882 by Winawer in a win over Blackburne. I guess the two moves will normally transpose.
5.0-0 e6 6.b3 Bd6
Morozevich chose 6...Ne7!? in a 1995 rapidplay win against Malaniuk (both players had ratings just above 2600). There are no other examples of the move in Mega19, and analysis engines Stockfish10 and Komodo9 disapprove, but it is dangerous to rely on engines' positional judgments in the opening.
7.Bb2 0-0 8.Ne5 Bf5!?
There is a lot to be said for 8...Bxe2. It exchanges White's good bishop, but also develops White's queen to a decent square.
 9.c4
An obvious alternative is 9.Nxc6 bxc6, but Black will be able to dissolve his doubled pawns. The engines continue 10.Nd2 (Stockfish10) or 10.c4 (Komodo9), with Black in each case replying 10...c5.
9...Nd7?!
The engines are not keen on this, preferring 9...Ne7 (Stockfish10) or 9...dxc4 (Komodo9). My idea, after a move such as 10.f4, was to evict White's knight with 10...f6, but then 11.Nxc6 bxc6 leaves Black looking vulnerable to a kingside pawn-storm.
10.Nxd7!?
This surprised me. The engines reckon it is enough for a slight edge, but they prefer 10.Nxc6 or 10.f4. Note that after 10.Nxc6 bxc6 White can prevent undoubling by 11.c5!?
10...Qxd7 11.Bd3?!
An old rule-of-thumb has it that when you have a bad bishop - in this case White's dark-square bishop, which is shut in by White's central pawns - you should not trade your good bishop. True, the dark-square bishop is doing a useful job in helping control the e5 square, and the coming exchange develops White's queen to a good square, but I do not believe these factors compensate for White's vulnerability on the light squares.
11...Bxd3 12.Qxd3 f5 13.a3

Black to make his 13th move

The stage is set for a battle of rival attacks - White on the queenside, Black on the kingside. Regardless of the merits of the two attacks, there will always be the realisation in both players' minds that White is playing for a long-term positional advantage while Black is playing for mate.
13...Rf6
I rejected 13...f4 because 14.Nd2 prevents an effective ...f3 as Black is not in a position to sac the exchange with 14...f3? 15.Nxf3 Rxf3?
14.c5!?
This comes to be Stockfish10's choice, at least for a while, but Komodo9 is unimpressed. As usual, pushing on like this is double-edged - it is certainly consistent with White's plan of queenside expansion, and it drives Black's bishop to an inferior square, but it means Black's kingside attack is less likely to be inconvenienced by central counterplay.
14...Be7 15.b4 Raf8
The engines do not like this, but I felt committed to playing on the kingside, and I wanted to be able to meet b5 with ...Nd8 without obstructing the a8 rook's route to joining the attack.
16.f4 h6?!
This may be too slow. I wanted to play 16...g5 but thought White was doing OK after 17.fxg5 Rg6 18.h4? h6 19.gxh6 Rxh6? 20.g3, which may be true. However, 19...Bxh4 is a major improvement.
17.Bc3?!
Komodo9 is happy with this move - for a while it is the engine's second choice - but if the idea is to stop b5 being met with ...Na5, then the idea is misplaced as 17.b5 Na5? 18.Nd2 will leave Black's queenside in disarray after a later Bc3 (indeed Stockfish10 reckons Black's best after 18.Nd2 is to sac a pawn with 18...Nc4 etc). However, having said all that, 17.Bc3?! does make the bishop better-placed for defensive duties on the kingside.
17...g5 18.fxg5?!
It was probably better to leave Black to open lines with an eventual ...gxf4 as g2 will be easier to defend than h2. Black could also push on with ...g4, but then will find it very difficult to open any lines on the kingside.
18...hxg5 19.b5 Nd8 20.Nd2 Rh6 21.Nf3 Bf6

White faces a tricky defence

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22.Ra2?
Best seems to have been 22.Be1. The point is that if play proceeds as in the game with 22...g4 23.Ne5 Bxe5 24.dxe5 Qh7, White defends h2 with 25.Bg3. The text also envisages a defence of h2, but at great positional cost.
22...g4 23.Ne5?!
Komodo9 prefers 23.Ne1 (but not 23.Nd2? Qh7) although Stockfish10 is unsure; either way, Black is well on top.
23...Bxe5 24.dxe5 Qh7 25.g3 Nf7
White's light-square weaknesses (see note to White's 11th move) mean he is lost despite the material balance.
26.e4!?
Objectively this cannot be good, but trying for counterplay may be White's best practical choice.
26...dxe4 27.Qd7 Ng5
Also tempting was 27...Rd8!? but there is no need to complicate.
28.Qxh7+ Rxh7 29.Rd1 Nf3+ 30.Kh1 f4
Simpler is 30...Kf7 (or 30...Kg7), meeting 31.Rd7+ with 31...Kg6, but the text also wins.
31.Be1
This is Stockfish10's choice for a while, but the engines come to agree that best was 31.gxf4, when Black has a pleasant choice between 31...Rxf4, 31...Rh3, 31...g3 and several other moves.
31...Nxe1 32.Rxe1 f3 33.Kg1 Rd8 34.Rf2 Rd4 35.Kf1 Rh5 (0-1, 45 moves)