Diplomacy is the Avalon Hill Game Company's trademark for its game of international intrigue, which game is copyright 1976 by Avalon Hill. Avalon Hill belongs to Hasbro.
The order notation in this document is as in DATC, with the following additions for multiversal time travel.
a-Munich@1. Where orders are not fully designated, the full designations are implied according to these rules:a-Munich is interpreted as a-Munich@2.A b-Tyrolia - Munich is interpreted as b-Tyrolia@1 - b-Munich@1.A a-Munich supports A b-Tyrolia - Munich is interpreted as A a-Munich@2 supports A b-Tyrolia@1 - b-Munich@1.A unit that moves into its own immediate past causes the timeline to fork.
Germany:
A a-Munich hold
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Germany:
A a-Munich - a-Tyrolia@0
A a-Munich@1 moves to a-Tyrolia@0. The main timeline advances to a2 with an empty board. A forked timeline advances to b1 with armies in Munich and Tyrolia.
A unit that supports a move that previously failed in the past, such that it now succeeds, causes the timeline to fork.
Austria:
A Tyrolia hold
Germany:
A Munich - Tyrolia
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Austria:
A Tyrolia hold
Germany:
A Munich supports A a-Munich@0 - Tyrolia
With the support from A a-Munich@1, A a-Munich@0 dislodges A a-Tyrolia@0. A forked timeline advances to b1 where A Tyrolia has been dislodged. The main timeline advances to a2 where A Munich and A Tyrolia are in their initial positions.
A unit that attempts to move into the past, but is repelled, does not cause the timeline to fork.
Austria:
A Tyrolia hold
Germany:
A Munich hold
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Austria:
A Tyrolia hold
Germany:
A Munich - a-Tyrolia@0
The move by A a-Munich@1 fails. The main timeline advances to a2 with both armies in their initial positions. No alternate timeline is created.
A unit that supports a move that succeeded in the past and still succeeds after the additional future support does not cause the timeline to fork.
Germany:
A Munich - Tyrolia
A Bohemia hold
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Germany:
A Tyrolia hold
A Bohemia supports A a-Munich@0 - Tyrolia
Both units in a1 continue to a2. No alternate timeline is created.
In this test case, a unit elsewhere on the map moves into the past to cause a timeline fork. Once there are two parallel timelines, a support from one to the head of the other should not cause any forking, since timeline forks only occur when the past changes, not the present.
Austria:
A a-Tyrolia hold
A b-Tyrolia hold
Germany
A a-Munich - Tyrolia
A b-Munich supports A a-Munich - Tyrolia
A a-Munich dislodges A a-Tyrolia. No alternate timeline is created.
Following 3.A.5, a cross-timeline support that previously succeeded is cut.
Germany
A a-Tyrolia holds
A b-Munich holds
Austria
A b-Tyrolia@2 - b-Munich@1
Cutting the support does not change the past or cause a timeline fork.