The players take turns in colouring regions on a map, such that two adjoining regions cannot be the same colour.
One of the players first draws a map consisting of a number of adjoining regions. The players then take turns in colouring a region, the first player using blue and the second player using red, with the restriction that two regions sharing a border cannot be the same colour.
The first player unable to move loses.
In the following game the first player, Blue, is unable to move and so loses: