Leela

    Keywords: Software

Leela
Author: Gian-Carlo Pascutto
License: proprietary
Price: 50€[1] (oct.'12)
Category: player
Operating system: Windows
Reads format(s): sgf
Writes format(s): sgf
Stable Version: 0.4.1 (march'12)
Development status: active
Homepage: [ext] sjeng.org
Size of installer: 1mby
Size if installed: 2mby
Strongest play: 1k[2] (sept.'08)
Plays online: LeelaBot, KGS

Leela is a Go playing program by Gian-Carlo Pascutto, author of the strong chess program Sjeng. As of February 2008, the website states that Leela plays at the 4 kyu level on a 19x19 board, and at a high dan level on a 9x9 board.

Table of contents

Features

  • board sizes 9x9 up to 37x37
  • rated games on 9x9 and 19x19 board
  • handicap up to 100 stones
  • auto adjust (rated games) or preset playing level
  • engine games on up to 37x37-board
  • show territory, show moyo
  • analyze mode
  • lite version plays free games on 9x9 and 13x13 boards; rated games on 9x9 board (there was also a free version around - 0.4.0, L.-lite - which plays free games on 17x17 and 25x25 boards)
  • plays always with komi x.5
  • asymmetric time settings possible (free games)
  • switch sides (by menu "Game" - "Force computer move")

Website

[ext] http://www.sjeng.org/leela.html

Implementation

According to its web site, Leela is a mix of different approaches. It seems to use a Monte Carlo engine, because when it wins, it wins with 0.5 points. Not so; it has won by larger margins when I have played against in on 9x9.

Strengths

  • Like other Monte Carlo programs, it performs well against traditional Go programs.
  • Leela likes to make a large moyo in the center, which often compensates for the opponent having all four corners.
  • Leela often finds interesting moves that really annoy its opponent, and I'm not sure yet whether these moves are tesujis or aji keshi.
  • In the opening, Leela often plays a shoulder hit, even against a stone on a hoshi. After doing this in some corners, these stones form a large but loose center moyo. If the opponent misses the chance to invade, this moyo becomes the winning factor.
  • Especially in the opening, Leela often plays moves that single-digit kyus want to answer, for example attaching at weak stones or enclosing a group in a corner. This means that Leela can often control what's happening on the board.
  • At any point of time, Leela has a good estimate of counting points, which may even allow abandoning a large group.

Weaknesses

  • Leela likes to play long sequences of ataris. Against weaker players this often works, but stronger players can easily beat the engine by playing solidly.
  • Like GNU Go, its impression about the status of groups isn't always correct, and sometimes it just misses to save a large group from being killed.
  • If you're a single-digit kyu player, you may try taking all four corners and then destroying Leela's center moyo. Just take care that the moyo border doesn't become water-proof. This works well for me.

Comment

moved to Playing Monte Carlo Programs

Remarks

  • [1] The cut down version Leela-Lite can be downloaded and used for free
  • [2] The development version named LeelaBot? has attained a [ext] KGS rank of 1 kyu as of September 2008. A sample of [ext] recent games is available via KGS as well.

This is a copy of the living page "Leela" at Sensei's Library.
(OC) 2014 the Authors, published under the OpenContent License V1.0.
[Welcome to Sensei's Library!]
StartingPoints
ReferenceSection
About