This technique allows Koichi to shoot down an opponent, giving him an option to retreat if he fails. First off, Koichi closes the distance to his opponent while mixing in some feints, then, while slipping past his feet, extends his leg sideways and hooks the foe's legs, tripping him. If the opponent manages to dodge the attack, and Koichi is being chased from behind, he makes an abrupt stop, turns around and trip him up. If his foe's being cautious and stops moving, Koichi just backs up and retreats.
By nature, Koichi movement's while using his Quirk are tough to get a read on. If his factor in his "trip up" diversion strategy, it will be all the more difficult for his opponent to step in to close range, and he can also make a smooth transition to escaping.