Trapezoid

The mouth or trapezoid is a template with a wide base. It is one of the most common interior templates after the bridge. The carrier of the template, i.e., the set of cells that must be empty for the template to be valid, has been marked "*".

Common patterns

Gaining Ground

The mouth can be used to steal territory. For example, in the following situation

Red can play as follows:

Ladder Escapes

The mouth also allows some ladder escape constructions.

Dominated cells

TODO:

Explain that some inner cells are dominated. See dead cell.