The term "Leg" is usually used in life and death problems. It usually describes a stone on the second line.
Door group with and without leg
In the diagram to the left, the right door group has a leg. It is the marked black stone.
Examples with two legs: door group and L group:
Door group with two legs
L group with two legs
Referenced byDoorGroupKanazawaProblem41...KanazawaProblem43...AnatomicalTermsKanazawaProblem70...