Japanese Kanji Readings: On'yomi vs Kun'yomi — When to Use Each

Section 1: What are on'yomi and kun'yomi?

When Japan adopted Chinese writing roughly 1,500 years ago, they faced a problem: Chinese characters represented Chinese sounds, not Japanese sounds. Japanese already had its own spoken language with native words for concepts like "mountain" (やま) and "water" (みず). The solution was to give each kanji two layers of reading:

• On'yomi (音読み) — the Chinese-derived sound. 音 means "sound," 読み means "reading." On'yomi are approximations of how the kanji was pronounced in Chinese. They tend to be shorter — often one or two syllables — and frequently appear in compound words (two or more kanji combined).
• Kun'yomi (訓読み) — the native Japanese reading. 訓 means "instruction / meaning." Kun'yomi attaches the native Japanese word to the kanji's meaning. They tend to be longer and often appear when the kanji stands alone or is followed by hiragana (okurigana).

Example: The kanji 山 (mountain) has the kun'yomi やま — the ancient Japanese word for mountain. It has the on'yomi さん — the Chinese pronunciation. When you write 山 alone or say "the mountain is tall," you use やま. When it appears in the compound 富士山 (Fujisan), you use さん.

Section 2: The 80% rule

Memorizing every reading for every kanji is a losing strategy. Instead, learn the rule that correctly predicts the reading in about 80% of cases:

• A kanji standing alone → kun'yomi (the native Japanese reading)
• A kanji in a compound word (two+ kanji together) → on'yomi (the Chinese-derived reading)

Examples of the rule in action:

The 20% exceptions to know: Kanji followed by okurigana (hiragana after the kanji as part of the word) almost always take kun'yomi even in compounds. 食べる (taberu), 見る (miru), 書く (kaku) — the hiragana ending signals a kun'yomi reading.

Section 3: 20 kanji with both readings and example words

Section 4: Kanji with multiple on'yomi or kun'yomi

Some kanji were imported from different Chinese dialect regions at different historical periods, resulting in two or more distinct on'yomi. This is called go-on (呉音) vs kan-on (漢音).

Section 5: Nanori readings in Japanese names

Nanori (名乗り) are kanji readings used exclusively in Japanese personal names and some place names. They are distinct from both on'yomi and kun'yomi and cannot be predicted from standard rules. This is why Japanese names are notoriously difficult to read — even native speakers sometimes cannot read unfamiliar names without asking.

Section 6: How to look up kanji readings

• Jisho.org: The best free online Japanese dictionary. Search any kanji to see all on'yomi, kun'yomi, nanori readings, example words, stroke order, and JLPT level.
• Furigana in reading material: When reading native Japanese content (manga, children's books, news with furigana mode), the small hiragana above each kanji teaches you readings in context — the most natural way to learn.
• IME typing: When you type Japanese on a computer or phone, the IME shows you which kanji matches what you typed. This passive exposure builds reading intuition quickly.
• The KANJIDIC database: Used by most dictionary apps. Any serious kanji study app (Anki, Takoboto, Jisho) draws from this database.

Common mistakes

• ✗ Reading 今日 as こんにち — it's an exception: きょう (not こんにちにち).
• ✗ Reading 明日 as めいじつ — it's あした or あす (kun'yomi exception).
• ✓ When in doubt: if the kanji has hiragana after it (okurigana), it's almost certainly kun'yomi.
• ✗ Assuming all kanji have exactly one on'yomi and one kun'yomi — many have two or more of each.
• ✓ Japanese names always require checking — do not guess based on standard rules.

Check your kanji usage in real sentences with ZISTICA MOJIIQ's free grammar checker — it catches misused readings and kanji errors instantly.

Frequently asked questions