Banquet (宴) is Kumeyuri’s intoxicating hallucination. Reinforced ears mitigate. A fatal wound can snap it. Chapter 76 is the issue titled for it. Chapter 75 titled Illusion. Play (遊) is the other named technique: move nearby objects; fluency scales with respect.
Not Crimson Recital
Uruha’s Koen is not a blade technique. It is the innate art that comes back when Samura cuts the contract and keeps the man. The banquet sword is the job. The recital is the person. Hiruhiko holds Kumeyuri in Uruha’s vacancy; Ro recovers the blade after the Hishaku extract Hiruhiko. Official chapters: VIZ / MANGA Plus.
File: chapter 76, Play, Kumeyuri, Crimson Recital.