The 4x3 triangle is a triangle made of three stones. Two are spaced 4 intersections wide with two empty spaces in-between with a third stone placed two intersections away from one of the stones with an empty space in-between. This creates two perpendicular "potential" lines. The 4x3 triangle is powerful because it allows you to form an open tria, forcing the opponent to respond, and then form a stretch tria immediately after. Eventually, when played correctly it allows you to form an H shape along with its potential for a double tria threat.