The Influence of Sea Power in Diplomacy

by Steve Jones
with apologies to Alfred Mahan 

Over the years, many excellent articles have been written discussing the tactics and strategy of playing Diplomacy, and have covered the gamut from opening theory to stalemate theory.  However, in all this, I don’t think anyone has discussed the global influence of sea power in determining the outcome of a game.  It is my contention that sea power can be vital to success in any game of Diplomacy, and that control of the seas is a decisive factor that tends to be overlooked by many players. 

Geopolitically, the Diplomacy board essentially depicts a peninsula surrounded by seas.  These seas can be conveniently sub-divided into regions of which there are four: 

(a)   The Atlantic: BAR, NWG, NTH, SKA, HEL, ENG, IRI, NAO and MAO.

(b)   The Mediterranean: WMS, GoL, TYS, ION, ADS, AEG and EMS.

(c)   The Baltic: BAL and GoB.

(d)   The Black Sea: BLA.

Within the context of the game, I define sea power to be control of sea spaces, and the exercise of that control to the benefit of a country’s overall strategic position.  These benefits are maximised if a player can achieve naval supremacy in a given region be destroying all enemy fleets in the region, or by rendering any existing fleets impotent by locking them up in a coastal province or an enclosed sea space (e.g. HEL).  Once full, or even partial naval supremacy is achieved the benefits that immediately accrue are (I) the capability of maximising the efficiency of your resources, and (ii) the rapid deployment capability and flexibility made available through the convoy order. 

Naval supremacy allows a power to increase the efficiency of its resources in a number of ways.  First, it usually implies that fewer pieces are needed to protect, or “police”, quiet areas of your empire, and this, in turn, releases resources for concentration in active areas leading to a build up of offensive momentum.  As an example, consider a France which has just completed its conquest of England with fleets in MAO, ENG, NTH, NWG and Edi, and armies in Bel, Pic, Bur and Lon.  Assuming Italy is neutral, the two armies in Bel and Pic and the fleet in MAO can be assigned to guard duty of mainland France and the Iberian peninsula, and no less than 6 active units can maintain an eastwards offensive momentum.  Secondly, the control of the seas usually enables the power concerned to conduct offensive operations with a reasonable degree of success where none would exist in the absence of naval supremacy.  As an example, consider an Austrian which has successfully conquered Turkey and Italy, and has fleets in GoL, WMS, NAf and TYS, and an army in Pie.  With such a position, Austria has an excellent opportunity of breaking into France and the Atlantic area; without the Mediterranean naval supremacy, Austria’s chances of breaking into France would be almost non-existent. 

The convoy order gives a power possessing naval supremacy in a given region an enormous degree of strategic flexibility and scope.  Any England which gains naval supremacy in the Atlantic region has the capability of convoying armies to France, Iberia, the Low Countries, Scandinavia and northern Russia, and also between any of those areas, and this capability is clearly of great strategic value, allowing armies to be switched from one front to another very rapidly.  Also, not only does the convoy order allow rapid movement of armies, it also implies that immediate back-up is available upon arrival in the form of support form the convoying fleet.  However, probably the greatest advantage of the convoy order is the element of surprise factor it affords. the classic example of this is the convoy of an army in Kie to Lvn by a fleet in BAL, allowing a follow-up strike at Mos; under the right conditions it can be a killer blow – I can still remember the first time I saw this happen in a Diplomacy game, and Russia never recovered from it.  A less surprisingly but equally classic example is the convoy of an army in Nap to Syr by fleets in ION and EMS, which, if successful, can destroy the usually strong Turkish defensive corner position.  However, it has been used so often in recent years as part of the Lepanto opening that it has lost its surprise element, and any Turkey worth his salt is well aware of it. 

No discussion of the influence of sea-power in Diplomacy would be complete without a discussion of the most strategic sea spaces on the Diplomacy board.  Without any doubt, the most important sea-space must be NTH.  With six supply centres, one non-sc and four sea spaces adjacent to it, possession of NTH is the key to the control of England and the Atlantic region.  If England ever loses control of NTH, his chances of surviving the game are slim at best; contrawise, any other power which succeeds in gaining and keeping control of NTH can often be considered to be on the way to a possible win. 

The second most important sea space is ION.  Although it only borders on two supply centres, possession of it is the key to the control of Italy and the central Mediterranean Sea.  Should Italy ever lose control of ION he is in serious trouble, and for Turkey possession of ION is vital for any chance of winning to be entertained.  The third most important sea space is probably MAO, and its importance arises from its location on the stalemate line running from the north-eastern to the south-western corners of the board.  Consequently, anyone seeking to set up a stalemate line will need to occupy it and be able to hold it; contrawise, anyone seeking to break a stalemate line, particularly form the east, needs to occupy it as well. The next two sea-spaces in importance are probably BLA and BAL; which one is more important in an individual game will depend on the strategic situation pertaining. the importance of BLA, apart form its obvious significance to Russo-Turkish relations early in the game, lies in the concept of the Lone Strategic Fleet: a situation which can arise anywhere on the board where one Power finds itself with a fleet in a sea space bordering many supply centres with all or most of those surrounding centres being controlled by another Power. In this case, the very existence of the fleet in BLA is an enormous strategic diversion to the surrounding Power with an effect out of all proportion to its size; it forces the surrounding Power to devote a large number of units to defend the coastal supply centres around BLA when they might be needed elsewhere. If the situation is right, this might allow the first Power or its allies to make inroads into the second Power’s position simply because he hasn’t enough resources to cover everything. This is admittedly an extreme example of the strategic value of a fleet in BLA, but I hope it highlights the value of F(BLA), which should never be underestimated. 

I should like to finish off this article by discussing the importance of sea power in the end-game.  Here, it can be a two-edged sword, in that it can be used to convert a draw into a possible win, or to prevent someone else from winning.  The most important strategic factor about sea power in the pursuit of a possible win is its potential stalemate line busting capability.  The possession of sea power in the right places makes it possible to get past troublesome bottlenecks like, for example, the Pie gap: the possession of sea power in the Western Mediterranean region makes it possible to push through this otherwise impregnable barrier.  The best way to consider the importance of sea power in setting up winning positions is to look at each country separately. 

Austria:  While Austria can win without any great naval capability, there is no doubt that the attainment of naval supremacy in the Mediterranean will give a big boost to any winning chances that may arise. 

England:  Sea power is absolutely vital for any English win to be possible, but does not guarantee it.  Unless England is fortunate enough to get lots of armies into central Europe fast enough, any English victory will require pushing fleets beyond Gibraltar, and the attainment of naval supremacy in the Western half of the Mediterranean region. 

France:  Virtually any French victory requires naval supremacy in the Atlantic or the Mediterranean or both; nothing else will do. 

Germany:  Germany is much like Austria in that winning German empires without any strong naval contingent are possible.  Nevertheless, if Germany gains naval supremacy in the Baltic and Atlantic regions, his winning chances are very good. 

Italy:  Italy is very similar to England in that he must have strong naval forces to have any chance at all, and yet this does not guarantee victory.  However, if Italy can break through Gibraltar into the Atlantic in force, his winning chances are very good. 

Russia:   Russia, of all the major powers needs naval supremacy the least.  Nevertheless, if Russia gets strong naval forces into either the Atlantic or Mediterranean, whilst remaining secure at home, victory is almost assured. 

Turkey:  Turkey is in the strange position of needing to dominate the “land ocean” from Mos to Mun in order to have any chance of even thinking of victory, and then requiring a strong naval presence in the Mediterranean in order to convert this into a win.  The eternal bug-bear of frustrated Turkish victory attempts is the impossibility of taking and holding StP in the face of opposition from a sea power in the north.  It is therefore essential for any Turkey to get fleets past Italy and into the Western Mediterranean area in order to pick up the elusive 18th centre from southern France and Iberia.  If Turkey cannot do this, his winning chances are almost non-existent, barring inept play from the opposition. 

While sea power can prove indispensable in setting up a possible win, it is equally true that it forms the basis of some stalemate lines. This usually requires the relevant Powers recognising the warning signs early enough and manoeuvring their naval forces into position; this is not always easy simply because it requires co-operation between the Powers concerned and a recognition of what is strategically required – and such considerations lie outside the scope of this article. 

In conclusion, the exercise of sea-power in Diplomacy is a very important factor in most games, and has a bearing on the outcome.  by appreciating the importance of sea power in the game, and learning how to exercise it to good advantage, a player may not gain victory, but he can greatly improve his chances of avoiding defeat. 

Reprinted from The Acolyte No.50 (August 1983)