Reversi Guide, Meaning , Facts, Information and Description

Some controversy surrounds the origin of the game. Many Japanese trace its origins to Japan in the 1970s, but some sources claim the game existed before that. Goro Hasegawa, who wrote How to win at Othello, popularised the game in Japan in 1975. It took its name from the Shakespeareanan play Othello, the Moor of Venice.

Mattel produces reversi equipment under the name Othello. Anjar Co licenses the registered trademark "Othello" from Tsukuda Original.

Analysts have estimated the number of legal positions in Reversi as 10²⁸ at most, and it has a game-tree complexity of approximately 10⁵⁸. In 1980 the program The Moor beat the reigning world champion, and since that time computer programs have competed near the world championship level. One of the world's strongest Othello AIss, Logistello, beat the human champion Takeshi Murakami 6:0 in 1997.

Human beings cannot generally win against computer intelligence in Reversi because computers can look ahead much further than humans can. Reversi has not yet been solved, however - we don't know the result of the game with perfect play on both sides.

When generalizing Reversi 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.

Play

  *o
  o*  (one of the possible starting positions)

  .
 .*o
  o*.
   .

  o
  oo
  o*

 .o.
  oo
 .o*

  o
  oo
 ***

Strategy

Pieces flip very quickly, easily and (often) repeatedly, so it offers little advantage -- and in fact typically bcomes disadvantageous -- to try to gain a majority of pieces early in the game. Corners, mobility, edge play, parity, endgame play and look-ahead form the key elements of good Othello strategy.

Corners

Corners, once played, remain immune to flipping: thus a player can use a piece in a corner of the board to anchor groups of pieces (starting with the adjacent edges) that also cannot be flipped. So capturing a corner often proves an effective strategy when the opportunity arises.

Mobility

An opponent playing with reasonable strategy will not so easily relinquish the corner or any other good moves. So to achieve these good moves, you must force your opponent to play moves which relinquish those good moves. The best way to achieve that involves reducing the number of available moves of your opponent. If you consistently restrict the number of legal moves your opponent can make, then sooner or later she will have to make a move undesirable to her. An ideal position to be in is to have all your pieces in the center surrounded by your opponent's pieces. In such situations you can dictate what moves your opponent can make.

When moves seem equal with respect to what moves you will leave yourself and will be open to your opponent, playing a minimum piece strategy will tend to be more beneficial. This is because minimizing your discs will tend to leave fewer discs for your opponent to flip in subsequent moves of the game. One should not play the minimum disc strategy to an extreme, however, as this also can quickly lead a lack of mobility.

Edges

While playing pieces to edges of the board may seem sound (because they are not so easily flipped) this can often prove detrimental. Edge pieces can anchor flips that influence moves to all regions of the board. Because of that, this can, sooner or later, poison later moves that you make by causing you to flip too many pieces and open up many moves for your opponent. However sometimes playing to an edge which cannot easily be responded to will leave your opponent with significantly fewer moves than any other moves.

The square immediately diagonally adjacent to the corner (called the X-square), when played in the early or middle game, typically guarantees the loss of that corner. Playing to the edge squares adjacent to the corner can typically lead to tactical traps involving sacrificing one corner, or simply playing out the edge in a specific sequence.

In general you should avoid edge play in the early and middle game if possible, unless you can gain larger concessions in terms of mobility or a mass of unflippable pieces.

Parity

As play progresses, regions of the board will typically section themselves off where neither side can prevent the other from playing arbitrarily into those regions. By simply counting out the number of squares in a region, one can notice if it is odd or even. If it is odd, then by playing there first, you can force your opponent to be the first to play outside of that region. This is achieved by simply playing into that region any time there is an odd number of squares available, and not playing into it when there is an even number of squares. If you take into consideration certain squares in a region that seem to be very bad (like an X-square or an edge square that leads to an obvious trap) then you can either force your opponent to play elsewhere or concede to playing one of these bad squares.

Look ahead and Endgame

As in any good strategy for chess or for checkers, it is not sufficient to only consider the current situation on the board. For each move you consider, you must consider possible responses from your opponent, then the subsequent responses you will make to those moves and so on. The aspects of the current position may not be relevant a few moves hence. So when optimizing your mobility, gaining corners or anything else, you should consider how best to do this for the long term rather than just for the next move.

For the endgame (the last 20 or so moves of the game) the strategies will typically change. Special techniques such as sweeping, gaining access, and the details of move order can have a large impact on the outcome of the game. At these late stages of the game no hard-set rules exist. The best you can do is try to look ahead and get a feel for what will lead to the best final outcome.

Game trivia

1. Since at least 1977 an annual Othello World Championship has taken place. Each country can send a maximum of 3 players.
2. Othello has its greatest following in Japan.
3. Good computer players far out-perform any human player.

Literature

• Othello: Brief and Basic, An introduction to strategy and tactics for the game of Othello, Ted Landau, 1987
• Othello: From Beginner to Master, Randy Fang, 2003

• The Othello Wiki Book Project
• A History of Othello
• History and Basic Rules of Othello
• Reversi guide
• The British Othello Federation
• The Danish Othello Assosiation
• The Italian Othello Federation
• The U.S. Othello Association
• Othello Blog

This is an Article on Reversi. Page Contains Information, Facts Details or Explanation Guide About Reversi

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