OTHELLO 

Traditional
Modern Rules: Copyright (c) 1971 Goro Hasegawa

Othello is a two player game played on a 8x8 square board, with the following setup:

 

DROP - Each player drops one stone of his own color on an empty cell, if at least one opponent stone is between that stone and another friendly stone (orthogonal or diagonal). All opponent stones that were between those stones flip their color. The flip may occur in more than one direction in the same turn. PASS - A player must pass if he has no valid drop. GOAL - When both players pass, wins the one with more stones.

 

An example [source] White has small mobility. How can Black achieve some advantage? Black plays at cell [1]. If White drops at h2, then Black continues with g3, then White must move g2, and Black has a superior advantage. If White drops at g3, then Black h7, White g7, Black h2, White g2, and Black wins again!

Quoting the Othello FAQ: The origin of Othello is not known. We have not seen any proof of rumors that Othello arose from an old Chinese game called ``Fan Mian'' (claimed in E. O. Harbin, "Games of Many Nations", Abingdon Press, 1954). Lewis Waterman and John W. Mollett (both of London, England) both marketed games with similar rules in 1880. Mollett's game was called Annexation and was played on a cross-shaped board. Waterman's game was called Reversi and played on the familiar 8x8 square board. It is unclear whose version came first, but Waterman's board and name are in use today.

Othello is one the most popular abstract games in the net. You can check the official rules of Othello and some other links. There are also a lot of variations (Reversi is a variant where the board begins empty, and both players alternate in dropping the 4 stones in the center board square) and known openings. Here is also some material about tactics and strategy. Check also this website (in spanish).

Other related games are MacBeth, Gomullo (on a NxN board, win by making a N in-a-row), Desdemona (there are grey stones. When a player flips an enemy stone, it becomes grey. If a player flips a grey stone, it becomes a friendly stone.), and Iago (players initially place neutral obstacles on empty cells that cannot be flipped). Another variant, called Sacrifice Reversi (by Patrick Duff) with an extra rule: Instead of making a regular Reversi move, a player can choose to flip one of his own stones on board. There's also a KO rule to avoid repetitions.

Reversi can be mixed with Seega (let's call it Reveega) on a NxM board. First phase, play just like Othello. When the board is full, the next player to move removes one stone and the other player continues by playing like Seega (moving to empty cells with custodian captures). When both players reach a sterile position, wins who captured more stones.

A Bill Taylor's Reversi variant, 1-11 Reversi, present a game where each player makes three moves on each turn in the following sequence: one friendly drop, one enemy drop and one friendly drop. In the end, the final game score is a legal Reversi game. Here is a game sample where the first player won 33-31 after some desperate final moves (I underlined the moves of the second player to ease the reading):

a b c d e f g h      
o o o o o o o x 1  d4  e4    11  g8  h8    21  b8  c8   31 b3  -- 
x x x x o o x o 2  d5  e4    12  g4  d6    22  d8  e8   32 g2  f2 
x x x x o x o o 3  f5  c4    13  e7  f8    23  b4  h6   33 h1  33-31 
x x x o x o o o 4  d3  f4    14  b2  a1    24  a5  a6           
x x x x x x o o 5  e3  f6    15  c7  c6    25  a7  c5 
x x x o x o o o 6  e6  d2    16  d7  c1    26  h4  f7 
x x x x o o o o 7  d1  c3    17  b1  g1    27  a2  a4 
x x x x o o o o 8  g5  e1    18  e2  b7    28  a3  g3                 9  g6  g7    19  a8  b6    29  h3  h2                                                10  f1  h5    20  c2  h7    30  b5  f3

Another Taylor variant is Biversi. On a 10x10 toroidal board, with two reversi start patterns (one crossed and one parallel) set up antipodal to each other. Play mechanics and game object as at Reversi, but with a 1222 progressive mutator. The two moves per turn must be played one in each section as long as they remain disjoint; after which moves may be played anywhere legal.

Here is an initial Biversi game:

a b c d e f g h i j  
o o . . x . . . . .  1.  . c4   d4 g9
. o x x . . . . . .  2. d3 f10  i8 d2
o o o x . . . . . .  3. a1 g6   e1 b4
. o o x . . . . . .  4. b4 i7   j7 a5
x x x x o . . . x x  5. a7 e5   f6 j10
. o . . . o o . o o  6. j8 i9   b6 b1
o . . . . . o o o o  7. b3 b10  j6 i10
. . . . . . o o o o  8. j5 c5   d5 i5
. . . . . . x o x .  9. h9 i6
. o . . . x . . x o 10.

In Impartial Othello (by Jeff Erickson) either player can place a stone of either color and flip stones of the opposite color. The winner is determined by the color of the last stone. So if there are more white pieces, and the last player played white, he wins.

As in Macbeth, Revertello (by Fred Horn, 2004) uses an hexagonal board. The game starts with the following setup:

Revertello rules are as in Othello but with an exception: the player must pick only two directions to flip stones (from the six possible).

Othello is one of those games where computers are better players than humans. Here is a list of several playing programs, you can check Ajax a pretty and pretty strong applet. You can also play and read extensive information about the game at the MindSports Arena.

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