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VOG — Vinco Online Games
Stable disks - positional strategy
           Diag. 2: Stable discs
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It is impossible to flip a disc placed in a corner since it can never
be flanked between two opponent's discs. A disc played in a corner is
therefore the most simple example of a stable disc. In addition, once
a corner is occupied by a disc, adjancent discs of the same colour often
also become stable discs.
In the example of Diag. 2, the 26 black discs are stable, independent of the colour of the other discs on the board, and black is assured to keep at least 26 discs at the end of the game. In Diag. 3, black may play to h8, creating 23 stable discs (the g and h columns, rows 7 and 8, and the disc f6) (see Diag. 4). Black is now in a very good position to win this game. Indeed, he already has 23 stable discs; if he can hold just 10 more discs at the end of the game he will be assured at least 33 discs, and victory. In Othello, discs played in the corners are therefore extremely important: they permit subsequent edge moves which lead to even more stable discs. However, this rule has exceptions (as we shall see later), but remember never to give a corner to your opponent without compensation (unless of course you have no better moves...). The simplest way to avoid giving up a corner is to avoid playing to the squares adjacent to a corner, that is to the weaker X and C squares (see Diag. on page 2). You may only move to a square which is adjacent to an opponent's disc (which you will flip); thus your opponent will not be able to take a corner unless at least one of the three adjacent squares are occupied. In Diag. 5, black has unwisely played to the X-square b7, believing that white cannot take the corner a8 since there is no white disc along the diagonal. However, white may play d8 (see Diag. 6), which flips (among others) d5 and allows him to take the corner a8 on his next move, black having no method to flip back the disc on d5. Indeed, the isolated disc on b1 will permit white to take the a1 corner: white plays c1, threatening to play a1 on the next move. To prevent this, black has only one possibility: he must flip back the disc by playing d1. However, thanks to the disc at e1, white may still play a1. Black has made a terrible error by playing the C-square b1. To be more precise, the danger of playing a C-square is greatest when it is an isolated C-square, that is to say not connected to other discs along the edge. Thus in Diag. 3, black has played several C-squares but he risks nothing since black discs occupy the entire edge. |
