In November 1932, he was transferred to Yokosuka Air Group, which was at the time considered an elite unit consisting of the very best fighter pilots in IJN.

During his four-year stay with Yokosuka Air Group, Mochizuki invented and developed hineri-komi (捻り込み—literal meaning: twist inside) maneuver that allows an aircraft, which is being chased by an enemy, to come at the chaser's tail or to gain an opportunity to take a shot at it.

Minoru Genda, who was also part of Yokosuka Air Group at the same time, observed this technique during the training sessions with Mochizuki and helped to formalize it in order to be widely adopted by other IJN pilots in dogfights.

The maneuver starts with a steep climb into a half loop, where the pilot applies (e.g., right) rudder to yaw his aircraft and performs a side slip.

After the resulting twisting motion, the pilot uses elevator to pull the aircraft up, which brings it into a horizontal flight in the same direction as the loop began.