Today we return to the topic of the effect of geography on strategy, introducing what is the single most important strategic element of the game: the stalemate line.
What is a stalemate line? In the hobby literature it is defined as any position controlling 17 or fewer SCs that can hold indefinitely against any attack.
An example will help. One such position (and the strategically most significant) is called the “Main Stalemate Line”. It roughly bisects the board, running from the southwest corner to the northeast corner nearly perfectly splitting the western from the eastern triangle (save for StP), leaving 17 SCs on each side. Here is a listing of the position as held from the southeast side:
F NAf S WMd
F WMd hold
F GoL hold
F Pie S GoL
A Trl hold
A Boh s Sil
A Sil hold
A Gal s Sil
A War hold
A Ukr s War
A Mos hold
A Sev s Mos
You can inspect that line and see no matter how an attacker on the northwest side of the line orders, they cannot dislodge any unit. That makes this an impregnable defense, a stalemate line. (I’ll leave it as an exercise for you to find the mirror of that line that stalemates an attacker on the southeast side.)
The presence of stalemate lines introduces another powerful effect of geography on strategy. The existence of a line in the expansion path of power may stop a march to victory. This makes crossing these lines (at least those that have 17SCs behind them) of paramount importance if you want to solo. For smaller powers, they provide a potential escape from the basic rule of Diplomacy that greater numbers always win. If you can obtain a stalemate line, smaller numbers can hold out indefinitely.
***** OPTIONAL READING *****
For a comprehensive discussion of stalemate lines, their uses and limitations, The Diplomatic Pouch’s “Stalemates A to Y” has a large collection of articles on the subject. Among them, is the indispensable “Visual Index to Stalemate Positions” by Matthew Self. Simply by clicking on a map that approximates your position, you are directed to an article with the stalemate lines obtainable in that vicinity of the map. There are a huge number of stalemate lines possible on a Diplomacy board, many of them minor variations of another. Self’s tool saves players from needing to memorize them all