From Halopedia, the Halo wiki
The achievement's name is a reference to the 1984 film The Karate Kid, in which the antagonistic Cobra Kai dojo advocates striking first, and striking without mercy. Sensei means both "teacher" and "first strike" in Japanese.
- Bungie.net: Bungie Weekly Update 07.09.10
- Windows Central, Halo Xbox 360 servers have been shut down, ending an era (Retrieved on Jan 23, 2022) [archive]
- Halo Waypoint, Sunsetting Halo Xbox 360 Game Services in 2021 (Retrieved on Jun 1, 2020) [archive]
- "Karate Kid" Script
- "Barticle's Japanese Mahjong Guide", page 27