The Shift-Right and Shift-Left variants of diplomacy follow the same rules as normal Diplomacy; the only difference is in the starting positions of the powers. The concept is simple: everyone begins the game with their units occuyping the home centers of another power, with the units that power would normally have at the start of the game. For example, in Shift-Right, Austria starts with F Edi, F Lon, A Lvp; England starts with A Ven, A Rom, F Nap; Italy starts with F Stp/sc, A War, A Mos, A Sev; and so on. Austria's home centers are still Austria's home centers--but he doesn't own any of them when the game starts, and can't build until he gets back to them. This is, of course, true for all the players....
Just as in regular Diplomacy: you must control a majority of the supply centers on the board, i.e. 18, regardless of how many units you actually have on the board. It is, therefore, theoretically possible to win without capturing a single onf of your home centers--unlikely, but you never know.
The starting positions for Shift-Right Diplomacy are as follows, where A -> B means "A's units start in country B":
- Germany -> Turkey
- Turkey -> Germany
- England -> Austria
- Italy -> England
- Russia -> Italy
- France -> Russia
- Austria -> France
Shift-Left Diplomacy shifts everyone in the opposite direction (Germany and Turkey still just trade); just reverse the arrows to see who starts where (or interpret A -> B as "B's units start in country A").