A specific type of Specialized Stance which is physically distinguishable by a 50%-50% weight distribution - Toe-Toe Heel-Heel Alignment (alignment of depth), feet approximately shoulder width apart (alignment of width), both feet positioned flat on the ground and pigeon toed; with both knees touching or almost touching at the center-line (alignment of height) - eyes directed toward the Point of Reference.

Comments:

The concave stance is essentially a double Close Kneel stance.

Defensively:

The concave stance is often used to defend the groin area from upward attacks.

Offensively:

The concave stance is often used to catch, trap, control, pin, and/or leverage Environmental Objects between the lower part of the legs.

The concave stance can be used to create a Vise-like maneuver against another Environmental Object, but this in rarely done, due to the natural resistance of the muscles to this position.

Derivation:

This stance derives its name from the fact that legs create a concave outline.