The Youngstown variant of diplomacy follows the same rules as standard
diplomacy with an expanded map. Three new powers are added: China,
India and Japan. The Indian player must use the letter "N" rather than
"I" when signing on since "I" is reserved for Italy.

The following is from a rules file of Jon Monsarrat:
A Bit of History...

The Youngstown game is the most popular of the many Diplomacy
variants. The reason, of course, is the minor modification and
expansion of the standard map to include the Major Powers of China,
India, and Japan. My best assumption for the origin of the variant is
that there is or was a large Diplomacy club in the Youngstown, Ohio
region. Apparently the variant was devised there and was quickly
dispersed through tournaments and word-of-mouth. I first saw the game
played at the Studio of Bridge and Games in Schenectady, New York.

Special Rules for the Youngstown variant of Diplomacy:

Impassable areas
No unit may enter Switzerland or the Himalayas. The body of water in
the center of the map is the Caspian Sea and is intentionally left
unlabelled and cannot be entered. No unit may enter the zone marked
"Impassable" north of Russia. Fleets may move along the coast of Omsk
as they did have icebreakers back then. Some subvariants disallow
this. If specifically disallowed by mutual consent of the players or
by decree of the game's master you should not order fleets to Omsk.
The adjudicator will permit such a move, however.

Off-board areas
Surrounding the edge of the map are "off-board" boxes. Various maps
differ in how they are identified. The adjudicator refers to the box
in the North Atlantic as "Offboard A", the Mid-Atlantic as "Offboard
B", etc. counterclockwise to "Offboard L"< in the North Pacific. The
off-board boxes allow a circular map to be represented on a flat sheet
of paper. There are several interpretations on how movement between
the off-board areas is intended to work. This adjudicator interprets
them based mainly on Jon Monsarrat's description:

1) Any unit in a land or sea area that contains an off-board box may
move into the box as though moving to a normal sea area or
province. Any unit in an off-board box may move into the sea area
or province which contains the off-board box.
Example: English F NAt -> ObA, Japan F ObK -> SPO
Off-board box C is contained within the South Atlantic. This is
indicated by an arrow since there is not enough room in that space
for the box.

2) A unit in an off-board box may move to an adjacent off-board box.
Example: French F ObB -> ObC, India F ObH -> ObG

3) A unit in an off-board box may move to the off-board box within the
sea area or province whose name appears in the unit's off-board box.
Example: French F ObB -> ObK, India F ObH -> ObC

If you have a copy of Ken Lowe's map, the spaces adjacent to an
off-board box are those listed within the box. It is recommended
that you have a copy of this map to play the game via the adjudicator.

4) Off-board boxes are treated as sea areas or provinces and hence,
only one unit may be present in an off-board box.

5) Support orders and convoy orders apply to off-board boxes.
Example:
Japan
F NPa C A Tok -> Ire
F ObL C A Tok -> Ire
F ObA C A Tok -> Ire
F NAt C A Tok -> Ire
A Tok -> NPa -> ObL -> ObA -> NAt -> Ire

England
F ObB -> ObK
F ObJ S F ObB -> ObK

6) A fleet may move to the African off-board boxes and is on the coast
of the African continent. Fleets cannot move to the inland off-board
boxes in Sudan and the Sahara (E and F).

The Suez
The Suez is a water territory contained within Egypt. It is adjacent
to the Eastern Mediterranean, the Red Sea and the north and east coasts
of Egypt. It is not adjacent to either coast of Jordan. Jordan's
north coast is adjacent to Egypt's north coast and Jordan's west coast
is adjacent to Egypt's east coast. Other units can move between Egypt
and Jordan whether or not there is a fleet in the Suez and fleets can
move into the Suez whether or not there is a unit present in Egypt.
Fleets in the Suez can convoy armies.

Victory Conditions
There are a total of 72 supply centers on the board. A majority of
pieces therefore would be 37 centers for victory by a single country.
A draw may also be declared by consent of all players or no exchange of
supply centers for three Fall seasons.

Initial unit placement and home centers for the Youngstown variant is:

England, France and Italy are free to build new units at their respective
colony territories with the same restrictions as regular home centers.

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