介 — “Jammed In / Shellfish / Mediate / Concern Oneself With” in Japanese

Master (高手)かい

Radical ⼈ · radical 9 The building block this kanji is filed under

“Jammed In / Shellfish / Mediate / Concern Oneself With” in Japanese is 介, read kai (かい). 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 紹介 (introduction).

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What does 介 mean?

Full details, readings & example

Kanji	介
Meaning	Jammed In / Shellfish / Mediate / Concern Oneself With
Readings	かい
Grade	Master (高手 · secondary school)
Curriculum	Jōyō kanji · Japanese secondary school (JLPT N1–N2)
Example	紹介 (introduction)

How to read 介

介 is read kai (かい) depending on the word.

Words with 介

紹介

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Kanji read the same way as 介

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

Updated: 2026-08-28