Rules and variants

Morpion Solitaire is played on a square grid, starting from a fixed cross of points (36 points for the 5-in-a-line game).

A move:

1. places one new point on a grid intersection, and
2. draws a straight line — horizontal, vertical, or diagonal — through n consecutive points, including the new one. All n − 1 other points of the line must already exist.

The score is the number of moves; play continues until no legal move remains. The goal is the longest possible game.

The touch rule

Two lines in the same direction that lie on the same track may not overlap by more than the allowed amount:

• Touching (T): parallel collinear lines may share one endpoint.
• Disjoint (D): parallel collinear lines must be strictly separate.

(Lines in different directions, or crossing, never conflict by this rule.)

Variants

All four are supported by the application and the MSR format. The exact coordinate frame, the initial cross, and the touch rule as a formula are defined normatively in the MSR specification.