What is the Japanese wording for unsheathing a sword (katana) for about half an inch with your thumb? I know that "tsuba" is the handguard that you use to push katana out of its scabbard and "nuke to" means to draw a sword I think. I'm curious how would you say/write down "draw a little bit of blade from the scabbard with your thumb via tsuba", which could indicate the intent of the blade wielder wanting to start trouble.

This is called . In some monolingual dictionaries, there is even an entry for it:

> ****
> ―
> Source: via kotobank.jp

the description roughly translating to

> Pulling out the blade a little bit so as to enable quick drawing of the sword. Loosening the mouth of a sword sheath.

_koiguchi_ literally means "carp's mouth", because, well, the mouth of the sheath resembles an open carp's mouth.

The verb _kiru_ has many different meanings ( lists 22 meanings) and here should maybe not be understood with its common meaning of "cutting" but probably with the meaning of "opening something sealed/closed" (point 3 in _ibid._ ).