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        Arimaa >> Off Topic Discussion >> Abstract strategy game: Othello (Reversi) 
        
(Message started by: W Mueller on Oct 14^th, 2008, 1:26am)

Title: Abstract strategy game: Othello (Reversi)
Post by W Mueller on Oct 14^th, 2008, 1:26am

Post Nr.1: A brief introduction from wikipedia:

Computer opponents

The best Othello computer programs can easily defeat the best humans. In 1997, Logistello defeated the human champion Takeshi Murakami in a score of 6:0.

By comparison, in Go and Arimaa even average human players can defeat the best computers.

Human beings cannot generally win against computer intelligence in Othello because computers can look ahead much further than humans can. Analysts have estimated the number of legal positions in Othello is at most 10^28, and it has a game-tree complexity of approximately 10^58.

Mathematically, Othello still remains unsolved. Experts have not yet figured out what the outcome of a game will be where both sides have perfect play.

However, analysis of thousands of high-quality games (most of them computer-generated) has led to the conclusion that, on the standard 8-by-8 board, perfect play on both sides results in a draw.

When generalizing the game to play on an n-by-n board, the problem of determining if the first player has a winning move in a given position is PSPACE-complete. On 4-by-4 and 6-by-6 boards under perfect play, the second player wins.

The following is the link of an excellent free program WZebra, dedicated for amateur Othello players:

http://www.radagast.se/othello/download.html

Title: Re: Abstract strategy game: Othello (Reversi)
Post by W Mueller on Oct 14^th, 2008, 1:28am

Post Nr.2 Weaknesses of WZebra's engine

WZebra tends to be somewhat pessimistic when evaluating the merits of a position. This is most easily spotted when Zebra is set to analyze a game; in an even position it will often find both players about 1 disk behind.

If a position which can never occur in an Othello game is created using the position editor, Zebra is likely to get confused and might make strange moves. This is because Zebra's knowledge was derived from positions taken from real Othello games, not random positions.

Title: Re: Abstract strategy game: Othello (Reversi)
Post by W Mueller on Oct 14^th, 2008, 1:31am

Post Nr.3 Edax

Intro

Edax is a software designed to play the game of Othello at a very strong level, mainly to offer a program to fight against other strong programs, but also to study games.

Details will be provided at later posts.

Title: Re: Abstract strategy game: Othello (Reversi)
Post by omar on Oct 21^st, 2008, 8:57pm

Thanks for this interesting info. I had no idea Othello was a win for the 2nd player on 4x4 and 6x6 boards. Imagine that, Zugzwang on the very first move :-)