by Andrew Poole

1) All the usual rules of Diplomacy (1971 rule book) apply except as amended below,

2) The game is for seven players, and is played on the regular Diplomacy board.  However, each of the Major Powers is able to build up to four tunnels.  A tunnel may be build between any two unconnected spaces on the board, passing underneath a third space which space which lies between them, e.g. from Lon to Pic under Eng.

3) When built, a tunnel allows an army to move, attack, or retreat from the province at one end of the tunnel to that at the other end, as if they were adjacent, e.g. A Lon-Pic; however, a unit may not give support through a tunnel.

4) A tunnel may be built under any one area on the board (except Switzerland), provided the entrance and exit to the tunnel are land provinces.  Two or three tunnels may be built from the same province, though each counts as a separate tunnel.

5) Each power may build only one tunnel in a turn, and the limit of build only four tunnels in the game means the construction capacity should be used sparingly.

6) A tunnel is build in secret by an army which has been ordered to stand in the province at one end of the planned tunnel, e.g. the player orders A Lon BT Pic, though the GM reports this as A Lon-H.  The existence of a tunnel remains secret even if the province at the other end of the tunnel is occupied during construction.

7) Only when a tunnel is used, is its existence made public, e.g. A Lon-Pic.  The owning power is free to use the tunnel as many times as they wish.  Units belonging to any other power are only able to use a tunnel with the owner’s express permission.

8) Otherwise, once a province at either end of the opened tunnel is occupied by the unit of another power, the tunnel is immediately demolished (after any retreats), and may no longer be used.  However, this does not prevent a second tunnel being constructed later along the same route.

9) If a second power orders, the construction of a tunnel which crosses under the route of an existing tunnel, the presence of the existing tunnel is not revealed to the other power (until it is used, as per Rule #7.)  Any tunnels that pass under the same province do not meet each other, even if built by the same power.

First published in Outposts #26 in December, 1987