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The Top Chess Engine Championship, Series 18 Superfinal finally concluded a few days ago, an epic battle in which Stockfish overcame Leela Zero by the score 53.5-46.5. It was fun to see the top two engines going head to head in games involving all sorts of different openings, and there were certainly some surprises (the Kings Gambit wins at 3800 level!). Luckily, Stockfish and Leela Zero contested some interesting lines in the Nimzo-Indian, Queen’s Indian and Bogo-Indian, so this allows us to take a glimpse of opening theory at a stratospheric level. Also included is an important update on a sharp Modern Benoni line we looked at last month.

Download PGN of June ’20 Nimzo and Benoni games

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Bogo-Indian: 4 Nbd2 0-0 5 a3 Be7 [E11]

4 Nbd2 0-0 5 a3 Be7 6 e4 d5 7 e5 Nfd7 8 Bd3 c5 9 h4!:

The emergence in recent years of 9 h4 has made this main line a major problem for Bogo-Indian players. It’s a problem that has by no means been solved, so it was intriguing to see 9 h4 provide the battleground between Leela Zero and Stockfish.

Black has to deal with the Greek Gift threat of Bxh7+, either with 9...g6 or 9...h6. In the first battle, Leela Zero had White and Stockfish chose 9...g6. 10 h5 is the obvious and most popular response, but Leela Zero instead preferred 10 0-0!?. This move seems slightly odd initially, but it has been played by Ding Liren and is equally dangerous to Black. True, White gives up some attacking chances down the h-file, but castling does allow the rook the chance to support the key e5-pawn with Re1. The game continued 10...Nc6 11 Nb3:

Previously we’ve considered 11...dxc4, played in Ding Liren-Saric,I/Batumi 2018. Stockfish instead chose to grab the h-pawn with 11...Bxh4!, which is a novelty.

Despite the two tempi spent taking the pawn and the inevitable retreat of the bishop back to the safety of e7, there’s certainly some justification for this capture. Of course, it’s useful to have a pawn in the bank, but its main merit is that ...Bxh4 actually removes a potentially key attacking unit against the black king. LCZero - Stockfish was an amazing game involving a deep queen sacrifice and pure domination from Leela Zero - an absolute classic!

In the next game, with Stockfish having White, Leela Zero opted for 9...h6. The game continued along a known path with 10 Bb1! (Planning Qc2) 10...cxd4 11 cxd5 exd5 12 Qc2 f5 13 Nb3 when the following position was reached:

Previously, Black has always chosen the obvious developing move 13...Nc6, and White has won the vast majority of the games. Here Leela Zero produced the unlikely looking novelty 13...d3!?. The point of this move isn’t immediately obvious, but Black’s clearly difficult situation requires creative play, and Leela Zero’s solution succeeds in changing the nature of the position. See Stockfish - LCZero for analysis.

Queen’s Indian: 4 a3 Ba6 5 Qc2 c5 6 d5 [E12]

4 a3 Ba6 5 Qc2 c5 6 d5 exd5 7 cxd5 Bb7 8 e4! Qe7 9 Bd3 Nxd5:

There are numerous lines in the Queen’s Indian where White meets ...c5 with d4-d5 and sacrifices a pawn. From White’s point of view, this particular example is certainly a favourable version of the theme. It’s noticeable that a2-a3, played to prevent ...Bb4 on move four, turns out to be extremely useful here in stopping ...Nb4!

Stockfish - LCZero continued normally with 10 0-0 Nc7 11 Bg5 f6:

In earlier games White’s bishop had normally retreated to either h4 or f4, but Stockfish preferred 12 Be3 and went on the provide a masterclass in attack. Games between 3800 chess engines haven’t altered the assessment of this line: somewhere between risky and unplayable for Black!

Modern Benoni, Taimanov Attack: 6 e4 g6 7 f4 Bg7 8 Bb5+ Nfd7 [A67]

6 e4 g6 7 f4 Bg7 8 Bb5+ Nfd7 9 a4 0-0 10 Nf3 Na6 11 0-0 Nb4 12 h3!?:

It was only last month that we looked at the rare choice of 12 h3 in the main line of the Taimanov Attack. Since then it was played by my Chessable White Rose teammate James Adair, in the final of the first ever 4NCL Online (happily for the team, we won!). I’m thankful to James for sharing his thoughts and analysis not only on the game continuation, 12...a6 13 Bc4 Nb6, but also on the critical line 13...f5! 14 e5! dxe5 15 d6+ Kh8 16 Ng5 e4:

In two games White has played 17 Be3 here. I also mentioned the possibility of 17 Ne6, but without going any further. James has succeeded in delving far deeper and concluded that the knight move gives Modern Benoni players some major problems to solve. See Adair, J - Wadsworth, M for James’s annotations.

Modern Benoni: 6 Nf3 g6 7 Bf4 Bg7 8 Qa4+ Bd7 9 Qb3 b5 [A61]

6 Nf3 g6 7 Bf4 Bg7 8 Qa4+ Bd7 9 Qb3 b5 10 Nxb5:

10 Bxd6 remains the critical move and we most recently looked at this in the game Studer,N-Donchenko,A/Moscow 2019. However, it’s been a very long time since 10 Nxb5 has been covered, and I was curious to see how modern engines assess it. In the recent game Stebbings, A - Hoffmann, H, Black responded with 10...Qa5+?!, which has been played a few times but looks slightly dubious. 10...Bxb5 is the recommended move, and I’ve provided an update on this within the notes. Modern engine analysis has made one or two minor tweaks, but the overall assessment is the same: Black is fine.

Nimzo-Indian: 4 e3 0-0 5 Bd3 c5 6 d5 b5 [E47]

4 e3 0-0 5 Bd3 c5 6 d5 b5:

Korchnoi unleashed 6 d5!? twice in his 1978 World Championship match against Karpov, but since then it’s been played only sporadically. Karpov responded with the typical gambit idea 6...b5. It’s probably because of this that 6...b5 is considered to be ‘mainline’, but it’s possible that alternatives are stronger. Leela Zero and Stockfish battled in this line, and both games continued 7 dxe6 fxe6 (I also consider 7...bxc4!? in the notes) 8 cxb5 Bb7 9 Nf3 d5 10 0-0 Nbd7:

As White, Leela Zero chose 11 Bd2, while in the reverse fixture Stockfish preferred 11 a3. In both cases, and especially so with 11 a3, White gained some advantage. See Stockfish - LCZero for analysis.

Nimzo-Indian, Dutch Variation: 4 e3 b6 5 Bd3 Bb7 6 Nf3 Ne4 [E43]

4 e3 b6 5 Bd3 Bb7 6 Nf3 Ne4 7 0-0 Bxc3 8 bxc3 f5:

7...f5 is considered to be the main line, although interestingly 7...Bxc3 has been played on more occasions. In the diagrammed position White can transpose to main lines with 9 d5 or 9 Qc2, but 9 Ba3!? seeks to exploit Black’s decision to exchange on c3 one move early.

In the all-engine battle Stoofvlees - Fire 8, Black grabbed a pawn with 9...Nxc3, and following 10 Qc2 Bxf3 11 gxf3 Qg5+ 12 Kh1 Qh5 13 Rg1 Qxf3+ 14 Rg2 Ne4 15 Rf1 we get to a position that is normally reached via the move-order 8...Nxc3!? (instead of 8...f5) 9 Qc2 Bxf3 10 gxf3 Qg5+ 11 Kh1 Qh5 12 Rg1 Qxf3+ 13 Rg2 f5 14 Ba3 Ne4 15 Rf1:

This was first seen in a game between Keres and Spassky in 1965, and since then it has been considered risky for Black. White is two pawns down but has far more active pieces than Black with many dynamic possibilities, and in practice White has scored heavily from this position. After 15...g6, Stoofvlees interestingly preferred 16 Qb2, a new move, despite the fact that both 16 d5 and 16 Be2 seem promising. Overall Black seems to be just about hanging on, but this is probably not a good practical line to choose as Black.

Till next time, John

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