While skimming through previous episodes of DanMachi, I happened to notice an amusing bit of animation in episode 3. At 11:34, Our Hero’s Dream Girl finishes dispatching a monster that’s escaped into the city, and as the crowd cheers, she performs a crisp, precise chiburi-nōtō to put away her sword. Her slim, double-edged rapier.
It’s an overhead crowd shot, and you only see her at a distance, but after flicking the blade clean, she very clearly grasps the mouth of the scabbard with her left hand and slides the full length of the blade along it before guiding it in.
It’s the classic technique for safely sheathing a katana, gliding the thick spine along the web of your thumb until the tip drops neatly into the mouth, so that you know without looking that the blade will go into the scabbard and not, say, your thigh.
This does not work for double-edged blades (or for that other famous anime blade, Rurouni Kenshin’s “reverse katana”). Attempting a standard nōtō will simply slice open your hand.
Amusingly, all of the close-up scenes I found of Aiz sheathing her blade show her just poking the tip into the scabbard; it’s only in this one very public slaying that the animators added the extra dramatic motion.
…and of course the usual ridiculous metallic noises that accompany waving a blade in the air and sliding it into a leather scabbard. After a while you sort of stop noticing that nonsense, unless it’s something as over-the-top absurd as the magical kitchen knife in the pilot episode of Gotham.