[Fenrir_valindri]

Wow, that move was very impressive:

Spoiler for 348:

Even with as powerful as the Elder's techniques are I really am impressed, it took Ethan down with one hit! Also, glad to see Chikage decided to help out Ethan by telling Kenichi were his sister is being kept.

haven't seen the translated chapter yet, but I assume it was a powerful attack using the rotation of the entire body while striking at the opponents blind spot (thus getting hit by the full force of the technique).