Onyomi vs Kunyomi: How Kanji Readings Work
By the Kantan JLPT team · · 8 min read
Quick answer: On'yomi (音読み) is a kanji's Chinese-derived reading, and kun'yomi (訓読み) is its native Japanese reading. As a rule of thumb, kanji in compound words (two or more kanji together) use on'yomi, like 学生 (gakusei), while a kanji standing alone or followed by hiragana uses kun'yomi, like 学ぶ (manabu). The rule has exceptions, so the most reliable approach is to learn readings through real words.
Readings are one of the first things that make kanji feel hard. This article explains how the two reading types work and how to guess the right one most of the time. It's part of our complete guide to learning kanji for the JLPT, which covers study methods and a plan for every level.
What is on'yomi?
On'yomi means "sound reading." When kanji came to Japan from China, Japanese speakers borrowed the Chinese pronunciation along with the character, adapting it to Japanese sounds. Those borrowed pronunciations became the on'yomi.
On'yomi are usually short: one or two syllables like ガク, セイ, ニチ or ジン. Dictionaries and study materials usually write on'yomi in katakana, which is a handy way to tell the two types apart on a kanji card.
Some kanji have more than one on'yomi because they were borrowed at different times or from different regions of China. For example, 生 can be セイ (as in 先生, sensei) or ショウ (as in 一生, isshō, a whole lifetime).
What is kun'yomi?
Kun'yomi means "meaning reading." Japanese already had its own words before writing arrived, so people attached existing Japanese words to Chinese characters with the same meaning. The native word for "mountain" was yama, so 山 got the kun'yomi やま.
Dictionaries usually write kun'yomi in hiragana. Many kun'yomi are verbs or adjectives, so they often come with hiragana endings called okurigana:
食べる
taberu to eat (た is the kun'yomi of 食, and べる is okurigana)
大きい
ōkii big (おお is the kun'yomi of 大, and きい is okurigana)
Not every kanji has a kun'yomi. 電 (electricity), for example, is read only as デン. And some kanji have several kun'yomi, like 生, which appears in 生きる (ikiru, to live), 生まれる (umareru, to be born) and 生 (nama, raw).
How do you know which reading to use?
These patterns cover most words you'll meet at N5 and N4:
Kanji compounds usually use on'yomi
When two or more kanji form one word, they usually all use on'yomi:
学校
gakkō school (ガク + コウ, with a sound change)
電車
densha train (デン + シャ)
毎日
mainichi every day (マイ + ニチ)
A kanji alone or with okurigana usually uses kun'yomi
A single kanji that forms a whole word, or a kanji followed by hiragana, usually uses kun'yomi:
山
yama mountain
見る
miru to see
高い
takai high, expensive
The exceptions
The patterns above are tendencies, not laws. Watch for these cases:
- Single kanji with on'yomi. Some words are one kanji read with its on'yomi: 本 (hon, book), 肉 (niku, meat), 駅 (eki, station), 気 (ki, spirit or mood).
- Compounds with kun'yomi. Some compounds use kun'yomi for both kanji: 名前 (namae, name), 出口 (deguchi, exit), 手紙 (tegami, letter).
- Mixed compounds. A few compounds mix the two types. 毎朝 (maiasa, every morning) and 本屋 (hon'ya, bookstore) are on'yomi + kun'yomi. 場所 (basho, place) and 手帳 (techō, planner) are kun'yomi + on'yomi.
- On'yomi + する verbs. Many verbs are an on'yomi compound plus する, like 勉強する (benkyō suru, to study).
When you're unsure, look up the whole word, not just the kanji. That's the main reason to learn kanji through vocabulary.
What is rendaku?
Rendaku is a sound change where the first consonant of the second part of a word becomes voiced: k becomes g, t becomes d, s becomes z, h becomes b. It happens most often in compounds that use kun'yomi:
| Parts | Combined word | Reading |
|---|---|---|
| 手 (て) + 紙 (かみ) | 手紙 | てがみ (tegami), letter |
| 出 (で) + 口 (くち) | 出口 | でぐち (deguchi), exit |
| 人 (ひと) + 人 (ひと) | 人々 | ひとびと (hitobito), people |
| 時 (とき) + 時 (とき) | 時々 | ときどき (tokidoki), sometimes |
There's no fully reliable rule for when rendaku happens, so learn these words as you meet them. The JLPT's kanji reading questions sometimes test these details, so it pays to notice them.
What are special readings like 今日 and 大人?
Some words have a reading that belongs to the whole word, not to its individual kanji. These are called jukujikun (熟字訓). You can't build them from the readings of each kanji. You just learn them as words.
| Word | Reading | Meaning |
|---|---|---|
| 今日 | きょう (kyō) | today |
| 明日 | あした (ashita) | tomorrow |
| 昨日 | きのう (kinō) | yesterday |
| 大人 | おとな (otona) | adult |
| 一人 | ひとり (hitori) | one person, alone |
| 二人 | ふたり (futari) | two people |
| 一日 | ついたち (tsuitachi) | the first day of the month |
| 二十歳 | はたち (hatachi) | 20 years old |
Some of these words also have a regular reading with a different meaning. 今日 can be read こんにち (konnichi, nowadays), and 一日 can be いちにち (ichinichi, one day or all day). Context tells you which one is meant.
Many of these words are N5 vocabulary, so you'll meet them early. The good news is that they're common, so they stick quickly.
Examples of on'yomi and kun'yomi in common words
| Kanji | Meaning | On'yomi word | Kun'yomi word |
|---|---|---|---|
| 日 | day, sun | 毎日 まいにち (every day) | 日 ひ (day, sun) |
| 人 | person | 日本人 にほんじん (Japanese person) | 人 ひと (person) |
| 山 | mountain | 富士山 ふじさん (Mt. Fuji) | 山 やま (mountain) |
| 水 | water | 水曜日 すいようび (Wednesday) | 水 みず (water) |
| 月 | moon, month | 月曜日 げつようび (Monday) | 月 つき (moon) |
| 学 | learning | 大学 だいがく (university) | 学ぶ まなぶ (to learn) |
| 生 | life | 学生 がくせい (student) | 生きる いきる (to live) |
| 大 | big | 大学 だいがく (university) | 大きい おおきい (big) |
| 食 | eat | 食事 しょくじ (meal) | 食べる たべる (to eat) |
| 行 | go | 銀行 ぎんこう (bank) | 行く いく (to go) |
| 出 | exit | 出発 しゅっぱつ (departure) | 出る でる (to go out) |
| 休 | rest | 休日 きゅうじつ (day off) | 休む やすむ (to rest) |
Notice how each kanji keeps its meaning across both readings. That's why learning the meaning first, then readings through words, works so well. For a full set of beginner kanji with their readings, see the JLPT N5 kanji list.
Common mistakes
- Memorizing every reading of every kanji. A kanji like 上 or 生 has many readings, and some are rare. Learn the ones that appear in common words first.
- Applying the compound rule too strictly. Words like 名前 and 毎朝 break it. If a reading feels uncertain, check the whole word.
- Forgetting sound changes. 学校 is gakkō, not gakukō, and 手紙 is tegami, not tekami. Small changes like these show up in JLPT kanji reading questions.
- Reading jukujikun piece by piece. 大人 is otona, not dainin or ōhito.
Frequently asked questions
Which is more important, on'yomi or kun'yomi?
Both. Kun'yomi shows up in many basic nouns, verbs and adjectives, and on'yomi dominates in compound words, which make up a large share of intermediate and advanced vocabulary. You'll learn plenty of both just by learning words.
Do I need to memorize all the readings of a kanji?
No. Learn the readings that appear in the words you study. Rare readings can wait until you meet them in a real word.
Why are on'yomi written in katakana?
It's a dictionary convention that makes the two reading types easy to tell apart at a glance. In normal Japanese text, words are written with kanji and hiragana, and readings aren't marked this way.
Can radicals tell me how a kanji is read?
Sometimes. Many kanji contain a component that hints at the on'yomi, but the hint isn't always reliable. Radicals are more useful for meaning and dictionary lookup. Learn more in our guide to kanji radicals.
Learn readings in context
Kantan JLPT teaches each kanji through the words it appears in, so you learn its on'yomi and kun'yomi the way you'll actually see them. Spaced-repetition reviews bring back the readings you miss until they stick, and mock tests include JLPT-style kanji reading questions to check your progress.