孔 — “Cavity / Hole / Slit / Very” in Japanese

Master (高手)こう, く, あな

Radical ⼦ · radical 39 The building block this kanji is filed under

“Cavity / Hole / Slit / Very” in Japanese is 孔, read kou, ku, ana (こう, く, あな). It is a Jōyō kanji taught in Japanese secondary school (junior & senior high) — the 高手 · Master tier beyond the grade 1–6 Kyōiku set, and appears in words such as 瞳孔 (pupil).

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What does 孔 mean?

Full details, readings & example

Kanji	孔
Meaning	Cavity / Hole / Slit / Very
Readings	こう, く, あな
Grade	Master (高手 · secondary school)
Curriculum	Jōyō kanji · Japanese secondary school (JLPT N1–N2)
Example	瞳孔 (pupil)

How to read 孔

孔 is read kou (こう) or ku (く) or ana (あな) depending on the word.

Words with 孔

瞳孔

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Kanji read the same way as 孔

Same sound, different character — the classic trap. Compare them side by side:

Updated: 2026-08-28