Please note that this is the Narutopedia's article on the anime-only genjutsu used by Kosuke Maruboshi. If you are looking for the article on the taijutsu used by Kimimaro then you should head to Dance of the Willow.
The user waves their sword back and forth, which when seen by the target locks them in a genjutsu which causes them to hallucinate multiple waving arms. The movement resembles that of a willow tree blowing in the wind. With the enemy off guard, the user is free to cut them down.