"Willow" is one of the four Lost+Found styles.
Martial Style This style can complete a Harmonic Combo. The Willow style isn't the most damaging style, but what it lacks in raw power it makes up for in tenacity. Like the willow tree, an expert in this style uses flexibility to overcome an opponent's defenses, and once inside his guard, the whip-like successive strikes of this style wear down an opponent and finish him. The tall, leaping power attack of this style covers a great deal of ground, and can strike at a foe who is surrounded by guards.
The first part of the video shows Willow in its inital state. The second part shows this style with damage and speed maxed out.