哉 is a Chinese hanzi, listed here under the keyword “final exclamatory particle”. It is built from 𢦏 (harvest festival) and 口 (mouth). It appears as a component in 3 other characters in this index.
On KumiJi Glyph Explorer, open the parts search and type “harvest festival” + “mouth”. 哉 is among the results, together with every other character containing the same shapes.
Open 哉 in the interactive kanji search
to expand every part down to its smallest pieces, add your own names and mnemonic stories,
or search for other characters by their parts.