Leela Chess Zero Chess learned from scratch

WCCC Live Updates, Day 1

Live Updates, Day 1

Live Games

Round 1

Leela had white with Komodo (12 I assume). The game ended up in a TB draw (and there may have been a few opportunities to claim a 3-fold around move 93), but the flag fell. 0-1.

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More Info on 2018 WCCC


Live Games

if you want pgn’s, the links are of the form http://www.icga.org/live/round-2/games.pgn

More on the WCCC

First off a warm thank you to our Cyril Guyot (@Cyril on discord) who paid the late entry fee and convinced his employer, Western Digital, Research, to provide a monster machine with 8xV100’s to run leela. Cyril will be operating leela during the tournament. Hopefully some other community members will be there so he can take a bathroom break.

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Down Goes Stockfish! Down Goes Stockfish!

Leela Beats Stockfish

It’s happened before, but when it happens on a big stage at a longer time control against a Stockfish on TCEC’s beefy 43 core setup, you have to sit up and take note.

King Crusher was at the scene in record time with a video.

Note that Leela was running on a remote machine with two 1080’s (ti?). A rough estimate puts the Leela Ratio at around 0.5.

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A Little Mini-Update on TCEC



Like most TCEC posts, this one comes with many caveats. This is through a back channel, first off. Apparently, GPU is not off the table, even if it involves delaying season 13 for a while.

Again, take with a huge grain of salt.

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Leela Accepted in 2018 WCCC


Leela Accepted in WCCC

Leela Chess Zero has been accepted in the 2018 World Computer Chess Championships (WCCC). Looking at the WCCC participant list, we see we’re up against the following:

  • Chiron
  • Shredder
  • Jonny
  • Pauline
  • Booot
  • Hiarcs
  • The Baron
  • Komodo
  • GridGinkgo
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Project Update


Project Update

Continuous Integration

Continuous integration will enable us to build and test software as new code is checked in. It will also allow the latest builds to be available to the public.

Currently we have the following CI services enabled:

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Announcement on TCEC S13


It is likely there won’t be a GPU available in TCEC S13. The team has put up a TCEC page in the Wiki that outlines plans and options. Quoting from the text:

We suggest the following settings for TCEC Season 13:

In the likely case that no GPU is available, the MKL-enabled lczero v0.10 release binary previously used in S12 will be suitable for use in S13.

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An Intriguing Win Against SF9

Passed Pawns are Its Downfall

King Crusher has several new vids up. I particularly like this one, where ID395 sacs a piece for a long term advatage in the endgame.

Apparently the dev version of SF recognizes this as a mistake, but we’re getting close when the precursor to SF10 is a refuge.

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Leela is Bad at Endgames? Not So Fast.


[Here’s an analysis of Leela’s grasp of a fairly strategic endgame.

When the author mentions lc0, he’s actually talking about lczero v0.10.]

This position is an extremely deep and subtle ending that traditional engines have trouble with for several reasons. First, we can note that there are too many pieces on the board initially for current tablebases to provide a clear answer, though as we progress into the variations, tablebase hits will occur and provide us with clarity. The other reasons are all synergystic with one another: material stands at a significant imbalance in the traditional point count, it is not a highly tactical position with only one major piece for each side and no minor pieces, the pawn structure is relatively locked (white will not be keen to push the f-pawn), and in fact, white does in some variations threaten to set up a surprising, but known, theoretical fortress (for example, if both pairs of the g- and h-pawns are exchanged, and the f-pawn remains on f2, this is impenetrable).

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The Leela Ratio


Leela Ratio: What is it?

If you spend any amount of time around the Leela forums and chats, you’ll see an announcement about a gauntlet or match where IDXXX has defeated some vaunted engine. Maybe there’ll be a note about the time control and the GPU or the number of cores the opponent used. But you are often left scratching your head as to how strong or weak Leela was relative to their opponent.

Enter the Leela Ratio: LeR = 875 * leela nps/sf9 nps

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