Lichess was the host for a fascinating match on Saturday 30th March between GM David Navara and Leela Zero at knight odds chess. I had the privilege of commentating on the match and the complete recording is available here on my Silicon Road YouTube channel: https://youtube.com/live/b04MPlCSL24 All the games of the match are available here on the Lichess Events page: https://lichess.org/broadcast/leela-vs-gm-david-navara-knight-odds-match/match/U8CvXKoW#boards The Leela team blog article on the match is here: https://lczero.org/blog/2024/03/leela-vs-gm-david-navara/
This match was another artifact of the Leela WDL Contempt feature discussed in previous blog entries and my YouTube video series on “Crazy Leela” (https://youtube.com/playlist?list=PLxhvNMc95Uo9N6W48TUAyIwkjK0w1wHKj&si=IK9OpgsfWB-wktZ1) This feature turned out to also work very well in odds chess where playing the best moves is much less important than creating and maintaining tension, and where you frequently have to accept being even worse (adding a couple of extra pawn sacrifices to the initial piece odds for example) in order to create chances for a win. When I ran the statistics for the Leela knight odds bot for the past month, the results were quite astounding:
In games where the odds offered were the knight on b1, Leela scored a 2818 performance against an average ELO of 2389 with an average game length of 30 moves. This was across bullet, blitz and rapid
Bullet 472.5/511
Blitz 505/551
Rapid 57/61
In games where the odds offered were the knight on g1, Leela scored a 2901 performance against an average ELO of 2306 with an average game length of 27 moves. This was also across bullet, blitz and rapid though on a smaller number of games:
Bullet 95.5/99
Blitz 109.5/113
Rapid 32.5/33
Perhaps even more impressive than these already remarkable statistics was the quality of the games. I showed a few games of Leela’s before the stream and here are a few more!
LeelaKnightOdds – SiriusStripy (2510) Casual Bullet game lichess.org, 28.03.2024
1.d4
1…f5 2.Bg5 h6 3.Bf4 d5 4.e4 Nf6 5.e5 Ng4 6.h3 g5 7.hxg4 gxf4 8.gxf5
Black’s incautious opening has allowed Leela to mix things up already! Black is still however a piece up and Black has managed to exchange off a pair of minor pieces at least.
8…c5 9.Qh5+ Kd7 10.e6+ Kc7 11.dxc5
One noticeable feature about Leela’s knight odds play is how skilfully the pawns are used to restrict the opponent’s pieces. We’ll see several examples of this in the next few games.
11…Nc6 12.Qg4 b6 13.Nc3 d4 14.b4
Wow!!!
14…Kb7
14…dxc3 15.Rd1 Qe8 16.Qxf4+ Kb7 17.b5 followed by bring the light-squared bishop to f3 is terminal for Black!
15.Qf3 dxc3 16.Rd1 Qc7 17.b5 Bg7 18.bxc6+ Kb8
18…Qxc6 19.Ba6+ Kc7 20.Qxf4+
19.Be2 Bf6 20.0–0
It’s still not totally clear that White is winning – after all, starting with a piece less you can easily simply run out of steam! However, Leela simply keeps on throwing more pawns into the mix!
20…h5 21.a4 h4 22.a5 h3 23.axb6 Qe5 24.b7 hxg2 25.c7+
25…Kxc7 26.bxa8N+
Aaah!
26…Kb8 27.Rb1+ 1–0
Stunning!
LeelaKnightOdds – chessfootie123 (2712) Casual Bullet game lichess.org, 28.03.2024
1.e4
1…g6 2.d4 Bg7 3.f4 c6 4.Nc3 d6 5.Qd3 Nd7 6.Bd2 e5 7.dxe5 dxe5 8.f5
Not a good strategy against Leela in principle. With a space advantage on one wing top play with, Leela is quite lethal!
8…Ngf6 9.0–0–0 Qc7 10.g4
Another pawn sacrifice to gain time!
10…Nxg4 11.Qf3 Ngf6 12.h4 Nb6 13.h5
The pawns keep on coming!
13…gxf5 14.h6 Bf8 15.Bg5 Be7 16.Bxf6 Bxf6 17.exf5 Bd7 18.Ne4
Although Leela is still a piece down (as well as an extra pawn on top) you have to look carefully to notice it! Black’s pieces have very little scope and the black king is still uncastled.
18…Be7 19.Rg1 0–0–0 20.Rg7 Rdf8 21.Bh3
Black’s position is quite unpleasant. Black seizes the natural opportunity to activate the passive knight on b6, but Leela has some tactics prepared!
21…Nd5 22.f6 Bd8 23.Bxd7+ Qxd7 24.c4
Pinning the knight to the black queen on d7. That’s not the end of the story however as Black has a cunning resource!
24…Qc7 25.cxd5 cxd5+
with check! Black regains the piece! Has Leela been tricked?
26.Kb1 dxe4 27.Qf5+ Kb8 28.Rc1
No! The Black queen cannot save herself and keep protecting the c8–square. White wins the queen!
28…Qxc1+ 29.Kxc1 e3 30.Rxh7 Rxh7 31.Qxh7 Ba5 32.Qe4 Bd2+ 33.Kd1 Rc8 34.h7 a6 35.Ke2 Ka7 36.Qg4 Rc1 37.h8Q Re1+ 38.Kd3 Rf1 39.Qgc8 Kb6 40.Qhd8+ Kb5 41.Qc4# 1–0
Stunning once again!
LeelaKnightOdds (2000) – Batancr (2354)
Casual Blitz game lichess.org, 29.03.2024
1.d4
1…Nf6 2.Bf4 c5 3.d5 Qb6 4.f3 g6 5.e4
Leela offering the b2–pawn as well! Black is cautious however!
5…d6 6.Ne2 Bg7 7.Bc1
A change of tack from Leela! The pawn is protected and Leela looks to start gaining space.
7…Nbd7 8.a4 Qc7 9.Nc3 a6 10.Be3 0–0 11.Qd2 b6 12.Bh6
Intuitively you would expect Leela to always avoid exchanges in odds chess. However, Leela often makes exchanges in order to reduce the activity of the opponent’s position, thus enabling a more effective squeeze with the pawns. This works to perfection here.
12…Ne5 13.Be2 e6 14.Bxg7 Kxg7 15.g4 Bb7 16.g5 Ng8 17.f4 exd5 18.exd5 Rae8 19.0–0–0
A great move! Black was looking to return the extra piece for a pawn in order to break the flow of White’s initiative. Leela is having none of it! The bind is more important than material!
19…Nd7 20.Bf3 Ne7 21.h4 Nf5 22.h5
The space-gaining play continues!
22…Nd4 23.Qg2
Once again Leela doesn’t avoid the exchange of one of its minor pieces for an actively-placed black minor pieces. The remaining bishop on b7 and knight on d7 would look slightly sad!
23…Re3 24.hxg6 fxg6 25.Qh2 Rh8 26.Bg4 Nf8 27.Qf2 Qe7 28.Kd2
A lovely little move and the rook on e3 is trapped! It can’t be defended by the other black rook which has been reduced to passivity, defending h7 and hemmed in by the equally prospectless knight on f8.
28…Rxc3 29.bxc3 Nf5 30.Bxf5 gxf5 31.Rde1 Qf7 32.c4
This now looks like a normal position in which White has sacrificed 2 minor pieces for a rook! Once again notice how helpless Black’s minor pieces are against the pawn chain that Leela has erected!
32…Ng6 33.Qe3 Bc8 34.Qc3+ Kg8 35.Qb2
Stretching the play by attacking a weakness on the queenside.
35…Qc7 36.Re8+ Kf7 37.Rxh8 1–0
David was playing against a souped-up Leela bot running on TCEC chatter windfishballad’s monster Leela rig with 4*Nvidia 4090 GPUs! David however won the 10-game match convincingly 7-3 with 6 wins, 2 draws and 2 losses. One fascinating aspect of the recording is that after every 2 games, David would join the stream and give his thoughts on the games he’d just played. He revealed that he had taken the match very seriously, playing through over 250 games manually (Chessbase doesn’t allow you to use any of its normal features from a non-standard starting position) and working out a strong, classical schemes of development which he implemented in every game. In particular he’d developed 5 simple principles for himself that he endeavored to apply in every game:
- Keep the king safe
- Exchange queens when possible
- Keep the positions simple and quiet
- Don’t create technical weaknesses
- Take care about time handling
David also mentioned that he wasn’t sure beforehand what the result would be. He had played a few training games with mixed results but when he started well in the match, that gave him a lot of confidence to carry on and push through. Indeed David didn’t spare himself at all, even reducing the time control from 5 minutes + 3 seconds to 3 minutes + 1 second to give Leela more even chances! It was an extraordinarily impressive performance of true class and I think all of the spectators were in awe of the control David managed to exert on the match.
Davied started the match excellently, his strong openings giving Leela no chance to create any sort of imbalance. Any tactics in the position were too small to stop David from establishing a strong, solid position.
Game 1
Game 2
Game 3
Game 4
This was the first game where David didn’t manage to liquidate to an open or stable position and with a faster time limit (David reduced the time control to 3 minutes + 2 seconds after winning the first two 5 minutes + 3 seconds games easily) David struggled to resolve the position.
Objectively, David’s advantage didn’t decrease but with his time running short, it felt like Leela was making the running
With very little time left, the breakthrough in the centre proved too much for David to handle:
Leela Knight Odds (2000) – Navara,David (2688)
Casual Blitz game lichess.org, 30.03.2024
39.d5
39…exd5 40.Re2+ Kf7 41.Rce1
This switch back to the e-file took everyone by surprise! Black is still winning but walking on a tightrope!
41…Re8 42.Rxe8 Nxe8 43.g6+ Kf8 44.cxd5
The terrible point: the a6–knight is loose while the black king is pinned to the back rank by the g6–pawn. Black will end up 2 pawns up, but the poor position of the king causes everything to collapse
44…Rc5 45.Bxa6 Rxd5 46.Bc1 Bxa4 47.Ba3+ Nd6 48.Re6 Bd7 49.Rxd6 Rxd6 50.Bxd6+ Kg8 51.Bc4+ Kh8 52.Ke3 h5 53.Kd4 Bc6 54.f4 Bd7 55.Bf7 b5 56.Kd5 b4 57.Bc5 b3 58.Ba3 a4 59.Kd6 Bf5 60.Ke7 Be4 61.Kf8 Bf5 62.Bb2 Be4 63.Bxf6 1–0
Game 5
David struck back beautifully however with a wonderfully controlled game. Leela went for a reversed Czech Benoni structure
and David gave Leela no chance, methodically snuffing out any hope of counterplay while exchanging pieces.
Despite very limited time, David showed great patience and control using a long knight manoeuvre and invasion via the kingside to force the white a3-pawn to a4(!)
after which it was an easy prey for his pieces!
Game 6
Leela’s play surprised everyone as Leela headed into a king and pawns against king, knight and pawns endgame after a sharp opening. However, with time running short, David struggled to keep control of both sides of the board and Leela escaped with a cunning stalemate trick!
Leela Knight Odds (2000) – Navara,David (2688)
Casual Blitz game lichess.org, 30.03.2024
David has managed to stop the white king from invading on the queenside, but almost too well!
41.a4 Kh6 42.g5+ Kxh5 43.g6 Kxg6 ½–½
Stalemate!
Game 7
David shortened the time control to 3 minutes + 1 second and this proved fatal to him as Leela put all sorts of obstacles in his path in the conversion of his extra piece.
With time running short and just a 1-second increment, it was hard for David to keep hold of all his isolated pawns and eventually he lost on time though Leela was clearly better by then.
Game 8
David traded to a position with Leela’s queen against rook, knight and bishop. David’s position looked very solid but Leela was once again very tricky. A blunder by David – perhaps his only one of the whole match! – left a bishop hanging but he was still able to hold the draw with rook and knight against queen!
Games 9 and 10
David finished in magisterial style giving Leela no chance in the final 2 games! Game 10 had everyone oohing and aahing with admiration. Leela reached this French-style position which looked like it might contain the seeds of future play…
…but David anticipated every move, swapping off the right pieces, blocking any pawn breaks…
…and inexorably creeping down the board without allowing an iota of counterplay – and all while playing faster than Leela!
It was a superb end to a convincing display and a very enjoyable match! Well done to David for the fantastic performance and the Leela team for their continuing efforts to push the boundaries of making engines useful for human training and instruction!