THE TOP Chess Engines Competition (TCEC) continues to throw up some amazing games. In the 18th series, Stockfish gained revenge over Leela Chess Zero, regaining its crown with a 23-16 victory (with 61 draws) in the final.
Arguably the most impressive win, though, was Leela’s from the 65th game, where the engines debated a critical and very modern line of the Bogo-Indian Defence. With 9 h4!, White threatens a Greek Gift sacrifice on h7 and it was noticeable that in the return game Leela opted for 9…h6 as Black.
LCZero – Stockfish
1.d4 Nf6 2.c4 e6 3.Nf3 Bb4+ 4.Nbd2 0-0 5.a3 Be7 6.e4 d5 7.e5 Nfd7 8.Bd3 c5 9.h4! g6 10.0-0!? Nc6 11.Nb3 Bxh4!? (A new move, as Stockfish typically displays no fear) 12.Bh6 Re8 13.Re1 cxd4 14.Qc2 dxc4 15.Bxc4 Nb6 16.Rad1 Bd7 17.Nc5!? (Spurning the pawn on d4 to maintain the initiative) 17…Rc8 18.b4 Nxc4 19.Qxc4 Be7 20.Ne4! Nxb4
It appears that White has blundered, but like its famous AI predecessor AlphaZero, Leela isn’t held back by traditional material values and now sacrifices its queen for two pieces and control of all the dark squares.
21.Qxb4!! Bxb4 22.axb4 (White has just two knights for the queen and three pawns, but Nf6+ Kh8; Rxd4 followed by Rh4 is a serious threat) 22…f5 (Desperate, but likely the only good defence, as if 22…Rc4 23.Nf6+ Kh8 24.Ng5 Re7 25.Rd3! when 25…Qb6 26.Rh3 Qxb4 27.Rf1 Rc3 28.Rh4! Bb5 29.Ngxh7! Bxf1 30.Nf8 leads to mate, 25…Qc7 26.Ngxh7 Rc3 27.Rxd4 Rc4 28.Rd3 Rc3 29.Rd6! leaves White with a mammoth, likely decisive bind, and 25…Be8 26.Ngxh7 Rc3 brings about today’s puzzle – see below)
23.Nf6+ Kh8 24.Rxd4 Rc7 25.Red1 Re7 26.b5! (Black has avoided losing material down the d-file, but is extremely tied down and Leela now makes it look like a forced win)
