Fumikomi is the space just inside Sadoguchi. This space belong to both guest and host. Therefore you should always pass though it if your going from the guests side to the host side, or the other way around. When passing though the guest need to take three steps, as they will change “direction” in walking. The fumikomi is considered the most geza place, and therfor they are walking towards a lower place when comming into the tatami, and will therefor cross the line with the fukusa foot. But when the progress out of the tatami again, they will be walking towards a more kami place, and will need to cross out of the mat using the non-fukusa-foot (usually right foot). Therefor they need to use three steps in this half mat.