秘

Phono-semantic compound:

祕 = 示 (“altar; to show,” semantic) + 必 (“certainly; surely,” phonetic)

The 示 radical gives the semantic element “hidden from sight / sacred matters,” since 示 originally relates to ritual and unseen forces.

必 provides the sound (pjit / 비).

Basic meaning:

숨기다 / 감추다 — to hide, to keep secret

비밀 — secret (as in 祕密/秘密)

Common Sino-Korean compounds:

祕密 / 秘密 (비밀) — secrecy; confidential

祕書 / 秘書 (비서) — secretary (originally “keeper of secret/records”)

祕策 (비책) — secret plan

祕錄 / 秘录 (비록) — secret record or chronicle

기밀(機密) commonly replaces it today in bureaucratic language.

The 示 radical gives an additional nuance of ritual secrecy / sacred concealment, similar to “esoteric” or “hidden from the profane.”

Hence classical works often use 祕 in a spiritual or ritualistic context.

Classical citations:

《史記·太史公自序》 (Records of the Grand Historian)

「藏之名山，傳之其人，祕不示人。」

“(I shall) store it in famous mountains, pass it to chosen persons, and keep it secret from others” — 祕 = to keep hidden; to conceal.

《後漢書·張衡傳》 (Book of the Later Han)

「其術祕而不傳。」

“His techniques were secret and not transmitted” — 祕 = secret; concealed knowledge.

《禮記·中庸》 (Book of Rites)

「神無方而易無體，故君子慎其獨也，以其祕。」

“The spirits have no fixed place, and simplicity has no fixed form; therefore the gentleman is careful in solitude, for it is in such moments that things are hidden” — 祕 = hidden; unseen.

秘 — variant form

Left side 禾 replaces 示 due to cursive simplification.

Originally just a calligraphic variant, later becoming the dominant modern form in Chinese and Japanese.

In Korea, 祕 is still taught in classical-education contexts, but 秘 is far more commonly used in everyday typesetting.

Orthographic practice in Korea:

Classical education and some Chinese textbooks → 祕

Modern printed materials, official documents, typography → 秘

Both are understood and used interchangeably.

In Korean encoding:

秘 is in KS X 1001 (front, black)

祕 is in KS X 1002 (back, blue)

This is why older Korean systems often displayed 秘 by default, even when 祕 was the intended standard form.

Confusion with 必-based characters:

Since 必 provides the sound, many 必-phonetic family members share similar readings (비/필), but meanings differ significantly (e.g., 必, 泌, 密).