On Yomi vs Kun Yomi

You look up 山 in the dictionary and find two completely different sets of readings: san and yama. You already know 山 means “mountain” — but which reading do you use, and when? Pick the wrong one and you’ll mispronounce 富士山 (Fujisan, not Fujiyama), or read 火山 as hisan instead of the correct kazan. The good news: there are clear, learnable patterns behind every kanji’s two reading types. This guide will show you exactly how on’yomi and kun’yomi work, when to use each one, and how to stop second-guessing yourself.

At a Glance: On’yomi vs Kun’yomi

What Is On’yomi (音読み)?

On’yomi (音読み｜おんよみ) literally means “sound reading.” These readings are derived from the way kanji were pronounced in ancient Chinese, brought to Japan between roughly the 5th and 9th centuries. Because kanji arrived in waves from different regions and eras of China, some kanji actually have multiple on’yomi — but more on that in a moment.

The most important pattern to know: when you see two or more kanji written side by side with no hiragana between them, you are almost certainly looking at on’yomi readings.

These multi-kanji words are called jukugo (熟語｜じゅくご) — compound words. They make up a huge share of Japanese vocabulary, especially in academic, professional, and formal writing.

Common on’yomi compounds you already know:

Notice: in every example above, you read the kanji using sounds that do not resemble native Japanese words. Den, wa, gakkou, nihon, shoku — these are Sino-Japanese syllables, not words Japanese people would have used before writing arrived from China.

What Is Kun’yomi (訓読み)?

Kun’yomi (訓読み｜くんよみ) means “meaning reading.” These are the original Japanese words that existed before kanji arrived. When the Japanese encountered Chinese characters, they matched them to words they already had. The kanji for “mountain” is 山 — but Japanese people already had the word yama, so they assigned that reading to the character.

The most reliable kun’yomi signal: when a kanji appears alone or is followed by hiragana (called okurigana), it is almost always read with kun’yomi.

Okurigana (送り仮名｜おくりがな) are the hiragana attached to a kanji that complete the word — especially verb endings and adjective endings. They are a clear visual cue that you are looking at a kun’yomi reading.

When you see 食べる, the 食 is read as ta (kun’yomi), not shoku (on’yomi) — because the okurigana べる tells you this is a native Japanese verb form. This is one of the clearest patterns in the entire kanji system.

Yuka

So if I see hiragana attached right after a kanji, that’s my cue to use kun’yomi?

Rei

Exactly! When you see kanji + hiragana like 食べる or 高い, the hiragana is part of the word. That’s okurigana — your sure sign that the kanji is being read with its Japanese (kun’yomi) pronunciation.

The General Rules: When to Use Which Reading

You do not need to memorize every reading of every kanji before you can use this system. These three patterns cover the vast majority of real Japanese text:

Rule 1: Two or more kanji together → On’yomi

When two or more kanji appear side by side with no hiragana between them, read each one with on’yomi. This rule holds true for the overwhelming majority of compound words (熟語).

▶ 電話 (でんわ) — not hikarihanaashi; it’s denwa (on + on)
▶ 学校 (がっこう) — not manabiie; it’s gakkou (on + on)
▶ 日本語 (にほんご) — three kanji, all on’yomi: nichi/ni + hon/moto + go

Rule 2: Single kanji + hiragana (okurigana) → Kun’yomi

When a kanji is followed by hiragana that forms part of the word (okurigana), read the kanji with kun’yomi.

▶ 食べる (たべる) — 食 is read ta (kun), not shoku (on)
▶ 読む (よむ) — 読 is read yo (kun), not doku (on)
▶ 高い (たかい) — 高 is read taka (kun), not kou (on)

Rule 3: Single kanji standing alone → Usually kun’yomi (but check)

When a single kanji appears on its own as a complete word — like a sign, a label, or a standalone noun — it usually takes kun’yomi. However, this is the loosest of the three rules, so it is worth verifying when you encounter unfamiliar words.

▶ 山 — yama (kun) when standing alone as “mountain”
▶ 川 — kawa (kun) when standing alone as “river”
▶ 火 — hi (kun) when standing alone as “fire”

These same kanji switch to on’yomi inside compounds: 火山 (かざん, kazan) = volcano; 河川 (かせん, kasen) = rivers (formal).

Yuka

This is so helpful! So 日 in 日本語 is on’yomi because it’s part of a compound — but 日 on its own is kun’yomi?

Rei

Right! 日 alone is read hi (kun’yomi) meaning “sun” or “day.” In 日本語 (nihongo) or 日曜日 (nichiyoubi), it uses on’yomi because it’s inside a compound. That one kanji has multiple roles depending on context!

N5 Kanji With Both Readings: Your Essential Reference

These ten kanji appear in the earliest stages of Japanese learning, and every one of them has both an on’yomi and a kun’yomi you’ll use regularly. Study the contrast between their readings in compounds vs. standalone use:

A useful observation from this table: the days of the week (曜日) all use on’yomi for the element kanji — 月曜日, 火曜日, 水曜日, etc. This is because 曜日 is itself a compound, pulling everything around it into on’yomi territory. Once you know this, you will read every day of the week correctly without thinking.

Kanji With Multiple On’yomi Readings

Some kanji arrived in Japan during different historical periods from different regions of China, so they accumulated more than one on’yomi. These are not errors — they are historical layers baked into the language. The most common examples at the N4–N3 level include:

生 — せい (sei) vs しょう (shou)

Kun’yomi: い (i) in 生きる (ikiru, to live); なま (nama) meaning “raw” or “fresh”

日 — にち (nichi) vs じつ (jitsu)

行 — こう (kou) vs ぎょう (gyou) vs あん (an)

This is one of the most extreme cases. 行 has three on’yomi and two important kun’yomi (い in 行く; おこな in 行う). The on’yomi you will encounter most are:

For multiple on’yomi kanji, do not try to memorize all readings in one sitting. Instead, learn each compound word as a unit. As your vocabulary grows, you will naturally absorb when each reading applies.

Exceptions: When the Rules Break Down (Jukujikun)

No rule in Japanese is without exception, and kanji readings are no different. There is a special category called jukujikun (熟字訓｜じゅくじくん) — words where the reading does not match any individual kanji’s on’yomi or kun’yomi. Instead, the whole word gets a single Japanese reading as a unit. These must simply be memorized.

The most important jukujikun for learners at this level:

When you encounter jukujikun, the kanji are essentially acting as a pictographic representation of a native Japanese word, not as phonetic guides. There is no shortcut — these must be learned as vocabulary items. The encouraging news is that the most common jukujikun (今日, 明日, 大人) come up so frequently that you will absorb them quickly through natural exposure.

Yuka

Wait, so 今日 is two kanji together, but it doesn’t follow on’yomi? I would have guessed konnichi not kyou!

Rei

You’re not wrong to think that! Actually, こんにち exists too — it appears in こんにちは (konnichiwa)! But as a standalone word meaning “today,” 今日 is read きょう. This is exactly why jukujikun are tricky — they’re the exceptions you just have to remember. The good news is there are not many of them.

The Right Strategy: Learn Words in Context, Not Readings in Isolation

The single most common mistake Japanese learners make with kanji readings is trying to memorize every on’yomi and kun’yomi for every kanji before learning any actual words. This approach leads to frustration, confusion, and rapid forgetting.

Here is a more effective approach:

• Learn kanji readings through vocabulary, not in isolation. Instead of drilling “山 = さん / やま,” learn 富士山 (Fujisan) and 山道 (yamadou) as separate words. The reading becomes attached to the word, not the abstract character.
• Use the patterns as a guide, not a guarantee. The on/kun rules will save you in most cases. When they do not, check a dictionary — and note the exception for future reference.
• Prioritize high-frequency kanji first. The 80 kanji in the JLPT N5 list appear in hundreds of words. Getting comfortable with those readings before moving to N4 makes the step up much less overwhelming.
• Read real Japanese as soon as possible. Even short NHK Web Easy articles expose you to kanji in natural context, which reinforces correct readings far faster than flashcard drilling alone.
• When in doubt with a compound, try on’yomi; when in doubt with a kanji followed by kana, try kun’yomi. This two-second check will be correct roughly 80–85% of the time.

Common Mistakes to Avoid

Surnames deserve a special note. Japanese family names (surnames) frequently use kun’yomi — sometimes mixed with on’yomi in unexpected combinations. 田中 (Tanaka) is たなか, not denshou; 山本 (Yamamoto) is やまもと, not sanpon. Treat surnames as vocabulary items with their own fixed readings rather than trying to decode them from rules.

Quick Quiz: On’yomi or Kun’yomi?

Look at each word and decide: is the underlined kanji being read with on’yomi or kun’yomi? Then check your answers below.

1. 水泳 (すいえい) — What type of reading is すい for 水?

2. 水 alone on a tap label — is it read みず or すい?

3. 書く (かく) — What type of reading is か for 書?

4. 図書館 (としょかん) — Is each kanji read with on’yomi or kun’yomi?

5. 大人 (おとな) — Does this follow the on’yomi rule for two-kanji compounds?

6. 高校 (こうこう) — What type of reading is こう for 高?

Answers:

1. On’yomi. 水泳 is a two-kanji compound (water + swimming). Both 水 (すい) and 泳 (えい) are on’yomi readings.
2. Kun’yomi: みず. A single kanji standing alone as a label is almost always kun’yomi. You would see みず on a tap or a bottle.
3. Kun’yomi. 書く has okurigana (く). That is the clearest possible signal: the kanji 書 is read か — its kun’yomi.
4. All on’yomi. 図書館 is a three-kanji compound with no hiragana between them: と + しょ + かん, all on’yomi.
5. No — this is jukujikun. 大人 should be daijin by the rules, but it is actually read おとな, a native Japanese word. Rules do not apply here.
6. On’yomi. 高校 is a two-kanji compound (high + school). 高 is read こう (on’yomi), not たか (kun’yomi).

Summary: Your Quick-Decision Guide

Mastering on’yomi and kun’yomi does not happen in a single study session — it develops as your vocabulary grows. Every new word you learn reinforces one more reading in context. Start with the patterns, use them as your first guess, and treat the exceptions as interesting puzzles rather than frustrating obstacles. Your kanji reading accuracy will improve steadily, and the day will come when you reach for the correct reading automatically.

Which kanji reading trips you up the most? drop your toughest example in the comments — our community and the team here at JPyokoso would love to help you sort it out!

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About the Author

Daisuke is the creator of JP YoKoSo — a Japanese learning site for English speakers. Every article is written to explain Japanese clearly, with real examples, grammar notes, and practical tips for learners at every level.

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