The Curse of Stalemate Lines
By Stephen Agar
If Diplomacy has any inherent design flaw aside from the improbability of finding as many as seven people within the same social circle who are willing to devote up to 6 hours at a stretch to play a boardgame, it is the fact that the game design is such that there is a reasonable chance that the game will never produce a winner. Indeed, a strong case can be made for saying that a well played game should never result in an outright victory. This situation would be tolerable if it resulted from fierce diplomacy aimed at maintaining the status quo over the board, but it is more likely that the game will grind to a halt due to the inherent limitations in the design of the board.
The problem is, of course, the existence of stalemate lines. It is worth saying straight away that there are basically two sorts of stalemate lines:
(a) the "we can stop him from winning situation" where a group of players (usually two or three) combine to stop a strong player from reaching 18 centres; and
(b) the "I can stop them from winning" sort of situation, where the aim is to secure a portion of the board that an alliance cannot take, with the object of participating in a draw or hastening a situation where the alliance will break down.
Some purists would argue that (a) is not a true stalemate line if the line protects more than 17 centres, as in that case the defenders have a majority of the board and therefore should press home their advantage. However, that view is optimistic to say the least, and I can well imagine situations where a 18 or 19 centre stalemate area is a justifiable end position, especially if the defenders are several builds short, or have the wrong mix of units. Much of the literature on stalemate lines in the US concentrates on stalemate lines that protect a minority of the board and are designed to prevent elimination.
Therefore, the most that can be said is that a stalemate line is an arrangement of units on the board which, when following specified orders, form an impenetrable barrier which means that that none of the units in the stalemate line can be dislodged by any permutation of attacks and supports from units on the other side of the stalemate line. Of course, the stalemate line must protect from capture sufficient supply centres to sustain the units needed to form the stalemate line. It stands to reason that if a stalemate line contains less than 17 supply centres then it cannot be used to prevent a single Power from winning the game.
Unfortunately, Diplomacy is riddled with stalemate lines. This is a result of poor board design, compounded by presence of an impassable space in the centre of the board. It need not have been so. Indeed, many Diplomacy variants do not share this inherent weakness. Any player which has a good understanding of where the stalemate lines are on the board will undoubtedly have an advantage in the end stages of a game, and anyone who has ambitions to win games outright against quality opposition must make an early study of the subject.
As someone who has designed quite a few variants in my time, Ive often had to face up to the problem of stalemate lines. While it is easy to see that any space can be secured if it has supports from at least 50% of the adjoining spaces, stalemate lines are constructed from a series of such spaces next to each other and may require far more than 50% of adjacent spaces to be occupied in order to be secure. I like to think of the as being built up like a chain link fence - the units in the stalemate line can serve two purposes simultaneously, both to deny the enemy the economic value of the space concerned and to prevent the enemy from using it as a space with which to attack another space in the stalemate line (or a space adjacent to it). The continual need to prevent the stalemate situation being outflanked, means that these lines stretch out across the board until a position is reached whereby the line cannot be outflanked, due to the edge of the board or Switzerland.
Lets consider a minimal stalemate position using the example of the most common stalemate line the NE/SW line from StP to MAO. StP has six neighbours, but in the absence of hostile fleets in the northern oceans, it is easily protected by a support from behind the stalemate line which cannot be cut e.g. A(Nwy). To stalemate a southern foe, it is not necessary to have units in Livonia or Prussia to make the stalemate line contiguous, as BAL and GoB are impassable to armies and we are assuming that the southern power doesnt have a northern fleet (very, very unlikely). Indeed, the next space in need of protection is Berlin. If we put the last unit in this part of the stalemate line in Mun, then Berlin only needs a single support (say F(BAL) as it can only be attacked from Sil and Pru. Munich borders Switzerland and so has its flank covered, though it borders no less than seven spaces (Tyr, Boh, Sil, Pru, Kie Ruh and Bur). However, on the current model only Sil, Boh and Tyr are able to have enemy armies, so Munich can be rendered safe with supports from Kie and Ruh.
So thats a stalemate line: A(Nwy) S A(StP); F(BAL) S A(Ber), A(Kie) & A(Ruh) S A(Mun). Those seven units can tie up half of the board. Of course there are other variations on this theme, usually with the northern power occupying Lvn, Pru, War and Sil, but the basic premise is clear.
Stalemate lines connecting Switzerland to the SW corner of the board are even easier to construct, thanks to the MAO and the Iberian peninsula. If the southern forces have neither got a fleet beyond the straits of Gibralter and have not taken Spa/Por, then the MAO is made safe by a single support from NAO, IRI, ENG or Bre. A support from Por can make Spain secure, while Mar only needs a single support form Gascony or Burgundy. And there you have it. F(NAO) S F(MAO); A(Por) S A(Spa); A(Gas) S A(Mar) forms a stalemate line (other variations dispense with the need for Spa and Por but would require War and Mos to encircle sufficient centres). Add the two lines together and you get 13 units protecting an enclosed area that contains 17 supply centres, enough to deny any other power victory.
Elsewhere in this issue is a definitive article from Mark Berch which goes through the various stalemate line sin some detail, but they are many and varied the example above is merely intended as an example of how easy they are to construct.
If we were redesigning the Diplomacy map it would be necessary to make some radical map changes to eliminate the possibility of stalemate lines. Making Switzerland passable would make a stalemate line harder to put together, but it would not make them impossible. On the above example, if you didnt occupy Switzerland then you would need armies in War, Pru, Lvn, Mos, Sil and Bur (dispensing with Nwy), but that would be 18 units supported by just 17 centres. On the other hand, if you did own Switzerland, then just A(Bur) S A(Swi) would suffice. Other minor map changes which increase the number of possible attacks on key spaces would also reduce the likelihood of a stalemate (such as dividing Sevastopol into and eastern and a western half, which would make Mos difficult to hold). Another possibility is to eliminate a stalemate position is to abolish the edges of the board on which stalemate positions must rest, allowing movement direct from one edge to the other (usually via a Off-Board Box), though in theory stalemates could even exist on maps such as that. An easier solution is to change the rules and it is difficult to see how you can ever get a stalemate in a variant with multiple units.