This is a chuudan yoko uke, or mid-level side block, while moving forward in sanchin dachi. The movement of the arms, trunk and legs should be in accordance with each other, with the trunk or hips leading the way. The head and spine remain erect and in line with the trunk. The hiki ken, or non blocking arm, plays a key role in the coordination of the technique and should not be neglected. As the hips draw the advancing leg into and then away from the body, the body naturally crosses the center line; this is the essence of sabaki, or "side-stepping," an attack. The movement of the feet is such that they do not leave the surface of the floor but rather slide across it in suri ashi. The center of gravity of the body is thus maintained over the legs throughout the move. Breathing is harmonized with the body's motion. This technique is found in the kata Gekisai Daiichi.