祕

祕 is a phono-semantic compound:

示 (altar, ritual, spirit) – semantic element, often indicating something sacred or hidden;

必 (pil, certainly, surely) – phonetic element.

Semantic range:

- to hide, to conceal – as in 숨기다.

- secret, mysterious – as in 비밀 (祕密).

- sacred, esoteric – by extension, can mean hidden knowledge or arcane matters.

秘 – a variant form using 禾 (grain) instead of 示. This arose from cursive simplification of 示, and the two have been interchangeable since early times.

Korean usage: In Korean educational hanja lists, the standard form is given as 祕, but in actual digital encoding 秘 is primary (KS X 1001, black list) while 祕 is secondary (KS X 1002, blue list). In practice, the two are mixed freely in writing.

Japanese usage: Only 秘 is included in the Jōyō kanji (standard-use characters). 祕 is considered a non-standard form.