It has been something over two years now since articles exploring stalemate positions on the Diplomacy board began coming out. In that time, the subject has been treated in great detail, to the extent that with the publication of a few additional positions in the coming year, the entire field will most likely be nearing a state of exhaustion!
Being that this is the case, it is now time to consider some of the implications the distribution of these position may have on general practical play, in particular for the player who wishes to perform well in defensive as well as offensive situations.
To being with, the center of every stalemate position is one of Calhamer's "wicked witches": England and Turkey. Without possession of one or the other, an attempt to stalemate against a united opposition holding at least half the centers is probably doomed to failure. This suggests that for a player expecting trouble in the later stages of the game (and who doesn't?) high priority should be placed on securing the nearest wicked witch, either diplomatically or militarily as seems most appropriate.
The board may be divided into Western and Eastern halves. The Western half consist of England, France, Germany, Scandinavia, Iberia, the Low Countries and St. Petersburg. The Eastern half consists of the remainder, i.e. Italy, Austria, Turkey, the Balkans, Tunis, Moscow, Warsaw and Sevastopol. Either group of centers can be held in a stalemate position. However more importantly, most stalemate positions consist of centers from one group or the other, but not both. Exceptions, when they occur, tend to involve relatively improbable positions or minor exchanges of centers in the Western Mediterranean. In particular, the West may occasionally hold Rome, Naples and Tunis and the East may occasionally retain Marseilles, Spain and Portugal.
In any event, the clear implication is that gains on one's side of the board tend to be more easily defensible than gains on the other. It may then be prudent, again from a view of setting up a potential defense, to put one's own side of the board in order before embarking on adventures on the other.
The influence of that hole in the middle of the board known as Switzerland is apparent in many stalemate positions. In particular, Switzerland serves as an anchor for a great number of positions, with the actual lines emanating from it. The only exceptions, again aside from improbable positions, are certain English positions which assume complete, unopposed, dominance of Northern waters. For the East, Venice, Tyrolia and occasionally, Piedmont or Munich, can be critical. The West often finds itself in a somewhat less critical position regarding Switzerland, however Munich and Marseilles can be critical in preventing a win by a single Eastern power (usually Turkey).
More important to the West are two corner spaces: St. Petersburg and the Mid-Atlantic. St. Petersburg is a critical component in the land defense of Scandinavia by the West. In the opposite corner, the Mid-Atlantic (almost invariable in conjunction with Portugal) forms the anchor of the Western sea defense. Neither space is absolutely critical, however typically problems begin to multiply with the loss of either. The loss of both probably means the loss of the game, except under very special circumstance.
In addition to the spaces already mentioned, the Ionian is always crucial for the East. Exceptions occur only in improbable positions. Italy is important, although partial losses can be compensated for by Northern gains.
Conversely, Vienna, Rumania and Sevastopol are important, although partial losses can be compensated for with positional gains in the Western Mediterranean and the spaces around Switzerland mentioned earlier.
The implications of the existence of these critical spaces are two-fold: The defender or potential defender should be aware of the possibilities of their position and seek to secure the critical spaces which are or may be needed. Access to some of the published material on stalemate lines may be helpful. For the attacker on the other hand, these critical spaces are the places to concentrate the offensive. Break through and the enemy position crumbles. Fail and the draw may be forced. The important thing is to recognize which losses may be sustained and which may not be.