Premade variant games in JDIP: (All use the standard map of Europe.)
1898: The game starts in Spring of 1898 with each power having one unit. Each country must capture its other home centers before it can build in them.
Britain: Each English province is a supply center and Britain starts with six armies. Thus, Britain is the "strongest" country, but is unable to do anything until another player agrees to convoy one of his armies (or he is forced to rebuild one of his units and then builds a fleet after retaking the supply center).
Crowded: The standard map is used, with the exception of having a supply center in Ruhr. Each of the 35 supply centers starts out as a home center for one of eleven players. The original seven players start out with their normal units and positions and are joined by four new players: Balkan, Lowland, Norway and Spain.
Wing Units: A wing unit may move through any province, irregardless of whether or not it is a sea or land province. However, wing units cannot capture supply centers. This rule may be used with any of the above maps.
Alternate variant games:1492: This 4-player variant takes place on a map of the known world in 1492, when much of the globe was actually unknown to the Europeans. To supplement this initial map, the GM creates his own version of the rest of the world which connects on all sides with the known world, but need not have any resemblance to the real world as we know it. By making the majority, of the playing board unknown, the players have to 'discover' it gradually as did the early explorers.
Somewhat modified rules apply. MapAberration: A nine-player variant which covers a similar part of Europe as the standard map, but has great powers that might have existed if history had gone a little bit differently. Standard Diplomacy rules with a few slight modifications.
Map.African: This six-player variant uses the standard Diplomacy rules but takes place on a map of Africa.
Map.Ancient Mediterranean: The Ancient Mediterranean is a five player map variant based loosely on the powerful civilizations of that period and area; Rome, Carthage, Greece, Egypt and Persia.
Map.Battle of the Five Armies: This 7-player variant takes place in on a map set in Tolkein's Middle Earth. Unlike most Middle Earth variants, this one is a map-only variant which uses standard rules.
Map.Diplomacy Royale: This variant can be used with any map.
The rules have been heavily modified to include blood lines, royal families, marriages, binding agreements, titles, and more.
Diplomyopia: Reminiscent of the Blind variant, but considerably more involved, this was the first hidden-movement variant played in the UK.
The standard rules are augmented by rules governing what kind of information about movements is given to players based on the orders.
Octarine: This variant is based on Terry Pratchett's "Discworld" and uses the standard rules with a new map.
Map.Seeing is Believing: This variant can be played on a variety of maps. In this variant, only final positions are revealed to players but the actual moves ordered are not. So, for example, a power who is attacked is oblivious to that fact if the attack fails. Standard Diplomacy rules apply.
Sengoku: This eight-player variant takes place starting in 1570 on a map of Japan. Standard rules apply with minor changes regarding geographic locations and victory conditions.
Map.