why, how, when
曷 centers on questioning: asking why, how, or when something is the case. It is a classical interrogative character whose core idea is seeking an explanation or time.
曷 is an ancient interrogative character. The top 曰 is often associated with speech or saying, and the lower part 匃 may have contributed a phonetic element, but the exact historical development is uncertain.
The top 曰 looks like a mouth speaking, and the bottom 匃 resembles a person bending over with a question mark. Picture someone asking 'why, how, when?' with a puzzled expression.
For カツ, imagine a cat (kat) asking 'why?' with a tilted head: kat -> カツ, and the cat's curious meow matches the questioning meaning.