Leela
Keywords: Software
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
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
KGS rank of 1 kyu as of September 2008. A sample of
recent games is available via KGS as well.