Anyone who plays and studies Diplomacy can become a good tactician, for of the three elements of the game -- negotiation, strategy, and tactics -- the tactical element is the simplest and most predictable. Tactics is the ordering and arrangement of your units so as to accomplish your strategic objectives. The more numerous force usually succeeds and, if not pressed by time, never loses. Tactical problems can sometimes be solved with the help of mathematical game theory, but that is beyond the scope of this article. Little can be said about good tactics as a whole, but many individual points can be noted.
According to game theory, the best way to play a game is to maximize one's minimum gains -- assume that the enemy is a perfect player and move accordingly. When reduced to mathematics, this can involve a certain amount of probability, even in a game such as Diplomacy which uses no chance mechanism (dice). In terms of Diplomacy tactics it means that you must look for a move that will make gains regardless of what your opponent does, but always remember that there is rarely a single best move. Outguessing the opponent, whether by intuition or by probability, is part of the game. A gain can be possession of a supply center, destruction of an enemy unit, or, especially in Spring, occupation of a non-center space which will lead to capture of a supply center in Fall. Spring is the season of maneuver, Fall the season of capture. When you outnumber the enemy, you’re virtually certain to succeed if you don’t make a mistake and if unit mix and positioning don’t handicap you at the start of the war.
If you’re outnumbered or desperately need a quick advance to prevent a third player from gaining the upper hand, then you must take chances. Try to figure out how the enemy will move and then order your units to take best advantage of that move. You’ll probably get clobbered, but you might guess right and leave your enemy in all kinds of trouble and rather wary to boot.
Remember that in every case, tactics must be subordinated to strategy. A slow, delaying withdrawal in one area might be better than a flamboyant attempt to turn the tide if you’re doing well elsewhere.
I mentioned unit mix and positioning above. Numbers are important in Diplomacy, but other factors can alter the balance. The ratio of fleets to armies can be vital. If you have too many of one and not enough of the other you could be beaten by a weaker enemy. Each country tends to have a natural or average mix of units, as explained in part 2, and areas have obvious, optimum mixes as well. The Mediterranean area, including the adjacent lands (Italy, Iberia, southern Balkans, Turkey, Africa) is an area where fleets are much more valuable than armies. Central Europe is an army area. While this seems self-evident, all too many players fail to plan ahead when building new units. Think about where you intend to be two or three game years hence, and build units that will help at that time. After you’ve expanded to about ten units, it will take one or two years for new units to reach the battle lines -- plan ahead for it. Moreover, think about where you will build a unit before the opportunity comes, to avoid hasty decisions when faced with a time limit.
When you are doing well you need to expand as rapidly as possible, getting units behind the enemy's defensive stalemate lines before those lines form. I call this "headmanning," from the ice hockey term for moving the puck up to the most advanced attacker. In a sense the most advanced attacking unit "carries the puck" for the whole attack. If it is stopped, the entire attack will bunch up behind it. Get a few units out front as fast as possible, and let newly built units help destroy enemy resistance nearer your country. A single unit, leading a stream of units, can make the difference between success and failure of an attack which takes place several years hence. For example, when Turkey is expanding west it should headman a fleet into the Atlantic as soon as possible, probably before the last Italian center is captured, so that the western countries cannot seal Gibraltar (by F Portugal and F English S F mid-Atlantic).
When the units to headman aren’t available, a lone raider behind the enemy lines can cripple an enemy attack or defense for years. Most spaces in Diplomacy border with six other spaces. Although land/sea differences help, three to five units are needed to force a lone raider to disband for lack of a legal retreat. A common way to start a raid is to retreat after battle into enemy territory rather than toward home, but in many cases a wary opponent will make sure this isn’t possible.
Another trick of retreating, the "fast retreat home," can be worked with an ally. One player dislodges a unit of the other, who disbands it rather than retreat. This allows him to rebuild the unit at home at the end of the year, barring loss of a supply center. He can change an army to a fleet in this way or bring a useless unit back home to defend the motherland or help eliminate a raider.
Whether attacking or defending, write your orders carefully. Several times in almost every game, an unintelligible or miswritten order ruins a brilliant plan. Double check. It’s easy to write one thing when you mean another. Some players take advantage of this common failing by deliberately miswriting an order. This may confuse the enemy, but more often it’s a means of double-crossing an ally while pretending innocence.
Defense is often a slow, boring affair, but imaginative use of attacks is sometimes the only means of successful defense. For example, if Russia has A Bohemia and A Galicia, and Austria has A Vienna and A Rumania, it appears that Russia has a sure two to one against Vienna because Rumania cannot support Vienna. However, if Austria orders A Vienna-Galicia S by A Rumania, then the Russian will be stood off if he attacks with Galicia S by Bohemia (two vs. two) as he is likely to do. (If he attacks with Bohemia S by Galicia then A Rumania-Galicia would cut the support and save Vienna.)
Here is a more complex example. Russia has F Aegean and Armies Bohemia, Galicia, Rumania, and Bulgaria. Austria has Armies Vienna, Budapest, Serbia, and Greece. Outnumbered five to four, at first glance Austria seems certain to lose a center. Russia can concentrate two units on Vienna, two on Greece, and use Rumania to cut one support. If Austria merely "stonewalls" (Budapest and Vienna support each other, Serbia and Greece support each other) he is certain to lose either Vienna or Greece this season and another center next season. But if he attacks with all four units (Vienna-Galicia, Budapest-Galicia, Serbia-Bulgaria, Greece-Bulgaria) he may catch the Russian napping. If the Russian chooses to attack with Bohemia rather than Galicia, with Aegean rather than Bulgaria, his supports will be cut by Budapest and Serbia and his attacks will all fail.
Austria takes a chance, however, because he may lose two or even three centers rather than one to a cagey Russian player, as follows:
|A Vienna-Galicia (dislodged)
||A Bohemia S A Galicia-Vienna
|A Greece-Bulgaria (dislodged)
||F Aegean S F Bulgaria-Greece
On the other hand, despite the losses, Austria finds himself behind the Russian lines in Galicia and Bulgaria with Warsaw and Sevastopol open. If the Russian is an unimaginative tactician the risk of all-out attack is sometimes worth the beautiful result.
Nonetheless, an attack is not always the best means of disarranging the enemy. First, you can stand when your opponent expects you to attack and moves to block it. This will leave his unit(s) out of position and could even cost him a center. For example, France moves A Marseilles-Spain in Spring 1901 while Italy moves A Venice-Piedmont. Now France wants to protect Marseilles, but he wants to end the Fall season in Spain in order to capture it (Spring occupation is not sufficient). If France orders A Spain-Marseilles and Italy orders A Piedmont-Marseilles, France will defend Marseilles, capture Spain, and leave Marseilles open for a possible build. But if Italy holds instead, France is left with an army in Marseilles, no captured center, and no place to build a Mediterranean fleet to resist Italy further. This is a classic guessing game. More often than not France moves to Marseilles because he can’t afford to lose a home center.
Second, a nominally attacking unit can actually support a defender’s move in order to disrupt the defense. For example, in Spring 1901 Russia moves A Warsaw-Galicia while Austria orders A Vienna hold, A Budapest-Serbia. In Fall Austria wants to protect both Vienna and Budapest and capture Serbia, so he orders a self standoff: A Vienna-Budapest, A Serbia-Budapest. This is the classic means of defending three spaces with two units. Russia, however, may order A Galicia S Austrian A Serbia-Budapest. Then Serbia-Budapest succeeds (two vs. one) and Austria does not capture Serbia. Later in the game a similar situation can occur, but with Serbia now owned by Austria and a Russian unit in Bulgaria as well. Russia could order Galicia S Serbia-Budapest and Bulgaria-Serbia, capturing Serbia. In either case the Austrian can outguess the Russian by standing where he is. In cases like this, luck, intuition, and knowledge of your opponent (and game theory, if you know how to use it) are your tools. Even so, there is no way to predict the "best" move.
Finally, avoid centergrubbing. Position can be as important as possession of an additional supply center, especially in Spring. Don’t disarrange a good position in order to immediately capture an invitingly vulnerable center. You may sacrifice so much that you’ll soon lose that center and more besides. In particular, don’t open a hole in your line unless you’re sure you can close it before an enemy raider gets through. One enemy unit behind your lines can delay an entire offensive. Moreover, be wary of dislodging a defender where the defender can retreat through your lines into your rear. Don’t be lulled by the apparent simplicity of a position. Every good tactician pays attention to details that the less skillful don’t notice or don’t bother about.