GoAn ancient Oriental board game

Andrew Simons

Introduction

• 2 player game of skill.

• Popular in the Far East, growing in the West.

• Simple rules, extremely deep strategy.

• Hard for computers.

History

• Originated in ancient China ~2000BC.

• Spread to Korea and Japan, “Golden-Age” mid-19th century.

• Spread to West late 19th century.

• British Go Association founded 1953."While the Baroque rules of Chess could only have been created by humans, the rules of Go are so elegant, organic, and rigorously logical that if intelligent life forms exist elsewhere in the universe, they almost certainly play Go." - Edward Lasker, Chess International Master and founder of American Go Association

Rules (Basics)

• Black and White take turns to place stones on the intersections of a 19x19 board.

• Stones are not moved, but can be captured by filling all their liberties.

Rules (Scoring)

• 1 point per territory, 1 point per capture.

• Player with most points at the end wins.

White: 25 Black: 24

Rules (Suicide)

• You are not allowed to commit suicide (play a stone with no liberties).

Two Eyes Live

• A group with 2 eyes can never be captured, it is “alive”.

Strategy

• Surrounding game: 圍棋• Go is a game of balance:

1. Territory vs. Thickness

2. Attack vs. Defence

• Unlike Chess which is mainly analytical, Go also uses intuition, a lot of pattern matching and heuristics.

Computer Go

• Go is challenging for Artificial Intelligence.

• In 1997 IBM’s Deep Blue defeated Chess World Champion Gary Kasparov.

• An intermediate amateur Go player can easily beat the best Go programs.

Why Is Go Hard?

• A large board and high branching factor give a vast game-tree complexity of about 10360 compared to chess’s 10123.

• Difficult evaluation function.

• Hard to emulate the heuristics and pattern matching of humans.

• Brute force is not enough, Moore’s law → next century.

Recent Advances

• Monte Carlo techniques: play out many games with a simple move selection algorithm to the end where the evaluation function is much easier.

• August 2008 defeated professional 8 dan Myungwan Kim with a 9 stone handicap. Running on 800 processors, 4.7 Ghz, 15 Teraflops supercomputer (1000x Deep Blue).

Example Game

More Information

• Cambridge Go Society:

http://www.societies.cam.ac.uk/cugos/

• KGS Go Server:http://www.gokgs.com

• Sensei’s Library (Go wiki):http://senseis.xmp.net/

• Me