Fun fact: Sagume's "that's not it" can also be interpreted as "that's not so," and can potentially be a direct response to Rumia's catchphrase, "is that so~?"
\That's not it/
Sagume says this to Sanae in LoLK whenever Sanae makes an incorrect guess about why Sagume won't speak. It may become her catchphrase, especially since Touhou M-1 Grand Prix recently picked it up and ran with it.
