Sai

is a Kidō spell.

Description
The practitioner, pointing his/her index and middle fingers at the intended target(s), causes the target's arms to lock behind their back. The spell is usable on a single target or a significantly large group of people.

Incantation
Unknown.

Known Practitioners

 * Rukia Kuchiki
 * Renji Abarai
 * Fujimaru Kudō