Onyomi vs. Kunyomi: Japanese Kanji Reading Guide

The Same Kanji, Two Very Different Sounds

How 日 becomes both “nichi” and “hi” depending on context

日

ON’YOMI

ニチ / ジツ

Nichi / Jitsu

日曜日 (nichiyōbi): Sunday
本日 (honjitsu): Today (formal)

日

KUN’YOMI

ひ / か

Hi / Ka

日 (hi): Sun, day
三日 (mitsuka): The 3rd, three days

One character. Four valid readings. All correct, depending entirely on context.

Introduction

You’re staring at a kanji you’ve seen dozens of times in Anki, and you still can’t tell if you should say “nichi” or “hi.” Your flashcard helpfully lists three different readings. The dictionary adds two more. You pick one and move on, probably wrong.

This is the on’yomi and kun’yomi problem, and it confuses almost every new Japanese learner because nobody explains it clearly upfront. Instead, textbooks just list both readings on every kanji entry and leave you to figure out the patterns yourself. Some people do, eventually. Many others just accept that kanji are chaotic and memorize readings one word at a time without ever understanding why.

The good news: there’s a real structure here, and once you see it, a lot of the apparent chaos resolves into something predictable. Not completely, but enough to make educated guesses most of the time. This guide covers where the two reading systems came from, how they differ, and the practical patterns that will help you pick the right one.

Also written as on’yomi / kun’yomi, on-yomi / kun-yomi, or on yomi / kun yomi. Sometimes called “on reading” and “kun reading” in English. All refer to the same two systems.

Quick Answer

Onyomi (音読み) is the Chinese-derived reading of a kanji, borrowed along with the character itself. Kunyomi (訓読み) is the native Japanese reading, attached to the same kanji based on meaning.

Most kanji have at least one of each. Onyomi shows up mainly in multi-kanji compound words (jukugo), and it’s generally the more common reading type overall since Japanese has far more compound vocabulary than standalone kanji. Kunyomi appears in standalone words, verbs, and adjectives, usually with hiragana endings (okurigana). Dictionaries print onyomi in katakana and kunyomi in hiragana, which is the fastest way to tell them apart on the page.

A Brief History: How Japan Ended Up With Two Systems

Japanese didn’t originally have a writing system. Spoken Japanese existed long before anyone thought to write it down, and when Chinese characters (漢字, kanji) arrived from China via Korea somewhere around the 5th century CE, the Japanese faced a practical problem: how do you use a foreign writing system for your own completely unrelated language?

The answer they arrived at was to use Chinese characters in two ways simultaneously. First, they borrowed the Chinese pronunciation along with the character, a clunky phonetic transplant that became on’yomi (音読み), meaning “sound reading.” But they also mapped existing Japanese words onto these characters based on meaning. The character for “mountain” already had a Japanese word, yama, so that word got attached to the character too. That’s kun’yomi (訓読み), meaning “meaning reading” or “training reading.”

On’yomi: The Import

Chinese characters arrived in waves, via different Chinese dialects at different historical periods. This is why some kanji have multiple on’yomi: an earlier reading borrowed from Middle Chinese and a later one borrowed after the dialect had shifted. The kanji 行 has both kou and gyou as on’yomi for exactly this reason.

Kun’yomi: The Native Layer

Kun’yomi represent the original Japanese language: the words people were already using before writing existed. When a character arrived with a Chinese meaning, someone decided which existing Japanese word it matched and attached it. These readings often feel more “natural” because they’re the words Japanese people had been speaking for generations.

The result is a writing system that carries the weight of two entirely different language families. Every kanji is, in a sense, carrying both its Chinese history and its Japanese history at once. This is why kanji readings feel complicated. They’re not random; they’re the sediment of twelve-plus centuries of linguistic layering.

What They Actually Are

Before getting into the patterns, it helps to see the difference side by side with a concrete example. Take the kanji 山 (mountain).

Reading Type	Reading	Example Word	Meaning
ON’YOMI	サン (san)	富士山 Fujisan	Mount Fuji
KUN’YOMI	やま (yama)	山 yama	A mountain
ON’YOMI	サン (san)	山頂 sanchō	Mountain summit
KUN’YOMI	やま (yama)	山道 yamamichi	Mountain path

Notice that 山道 (yamamichi) is two kanji both read with kun’yomi, while 山頂 (sanchō) uses on’yomi for both. That pattern is not a coincidence. It’s one of the most reliable rules in the whole system, and we’ll get to it.

Dictionaries typically list on’yomi in katakana (サン) and kun’yomi in hiragana (やま). This convention exists specifically so you can tell them apart at a glance, so once you know this, those dictionary entries become a lot less mysterious.

Why Onyomi Is Written in Katakana

The katakana-for-onyomi convention isn’t random. It goes back to how katakana was used in the first place, and understanding it can actually make onyomi easier to remember instead of just another arbitrary rule to memorize.

Katakana Marks “Borrowed” Sounds

Katakana got its start over a thousand years ago as annotation marks that Buddhist monks scribbled next to Chinese texts to show how to pronounce them in Japanese. From day one, katakana was the script attached to foreign, imported sounds. That association never went away. Modern Japanese still uses katakana for loanwords like コーヒー (kōhī, coffee) or カメラ (kamera, camera), for exactly the same reason: it’s the script that flags “this sound came from somewhere else.” Onyomi is a borrowed Chinese pronunciation, so it gets the borrowed-sound script.

Hiragana Marks “Native” Sounds

Hiragana developed as a homegrown script for writing Japanese grammar: particles, verb endings, and the okurigana that attaches to kun’yomi words. Kunyomi readings are native Japanese words, so pairing them with the native script keeps the whole system internally consistent. It also lines up with how kunyomi words are actually written in real sentences, since the hiragana okurigana on a word like 食べる (taberu) is already doing the same job.

Using Katakana as a Memory Tool

Once you know why the convention exists, you can use it deliberately instead of just noticing it. A few ways this helps in practice:

Let the script do the sorting for you. If you write or drill a reading in katakana, you’re automatically telling your brain “this is the Chinese-origin one, expect it in compound words.” Writing サン instead of just “san” on a flashcard bakes that category into the visual, not just the sound.

Borrow the loanword association. You likely already have strong pattern recognition for katakana from reading loanwords like テレビ (terebi, TV) or アイス (aisu, ice cream). That same “this is a borrowed sound” instinct transfers directly to onyomi, since it’s a borrowed sound too.

Use the sound shape as a second signal. Onyomi tends to end in closed syllables like n, ku, or tsu, which is part of why it sounds distinctly “Chinese” to Japanese ears. Katakana’s blocky, angular shapes pair naturally with that harder-edged sound, while hiragana’s rounded shapes pair with kunyomi’s softer, open-vowel endings. It’s a loose association, not a hard rule, but plenty of learners find it sticks.

None of this changes how the words are written in real sentences: both onyomi and kunyomi vocabulary is normally written with kanji, not katakana or hiragana alone. But when you’re studying readings in isolation, in a dictionary entry or a flashcard, matching the script to the reading type turns an abstract label into a visual cue your memory can actually grab onto.

Key Terminology

These terms come up constantly in kanji study materials. Worth knowing them before they appear unexpectedly in a textbook footnote.

On’yomi 音読み

The Chinese-derived reading of a kanji character. Borrowed phonetically from Chinese pronunciation, though heavily adapted to fit Japanese sound patterns over time. Usually appears in jukugo (multi-kanji compound words). Shown in katakana in dictionaries.

Kun’yomi 訓読み

The native Japanese reading of a kanji character. Assigned to a character based on meaning: the Japanese word that already existed for that concept. Often accompanied by okurigana. Shown in hiragana in dictionaries.

Jukugo 熟語

A compound word made of two or more kanji. Most jukugo use on’yomi for all component kanji. Examples: 電車 (densha, train), 図書館 (toshokan, library), 日本語 (nihongo, Japanese language). This is where on’yomi dominates, and knowing this pattern saves a lot of guessing.

Okurigana 送り仮名

Hiragana characters written after a kanji that complete a word, particularly verbs and adjectives. They signal kun’yomi. If you see 食べる, the べる is okurigana; the kanji 食 is read as “ta” (kun’yomi). If you see 飲む, む is okurigana and 飲 is read “no” (kun’yomi).

Nanori 名乗り

Onyomi vs. Kunyomi vs. Nanori

Nanori is a third category of readings, used almost exclusively in Japanese proper names: people’s names and place names. Unlike on’yomi and kun’yomi, nanori readings don’t follow reliable rules, which is why Japanese names are notoriously difficult to pronounce from the characters alone. If you’ve ever been blindsided by a name reading, nanori is the culprit.

Jōyō Kanji 常用漢字

The 2,136 kanji designated by the Japanese government for general use in education and media. Each has an officially listed set of on’yomi and kun’yomi. This list is the standard reference for “how many readings does this kanji have?”, though real usage sometimes goes beyond it.

Core Differences

Beyond where they came from, on’yomi and kun’yomi differ in some observable ways that are actually useful for identification.

Feature	On’yomi	Kun’yomi
Origin	Chinese pronunciation (borrowed)	Native Japanese words
Typical length	1–2 mora (short: ko, sha, tsu)	Often longer (hikari, yasumi, nagare)
Dictionary notation	Katakana (コウ, ショ)	Hiragana (こう, てる)
With okurigana?	Rarely	Often (verbs, adjectives)
Common context	Compound words (jukugo)	Standalone words, verbs, adjectives
Formality register	Often more formal/technical	Often more conversational
Sound patterns	May end in ん, く, つ, き	Usually open syllables (vowel endings)

That sound pattern difference is worth dwelling on. On’yomi can end in n (ん), ku, tsu, ki, chi: closed syllables with consonant sounds at the end, which reflects their Chinese origin. Kun’yomi almost always end in an open vowel: a, i, u, e, o. When you encounter a reading and it ends in -n or -ku, that’s a strong signal you’re looking at an on’yomi.

ON Ends with consonant sounds

山 → サン (san), 日 → ニチ (nichi), 学 → ガク (gaku), 力 → リョク (ryoku), 国 → コク (koku)

KUN Usually ends with a vowel

山 → やま (yama), 日 → ひ (hi), 学 → まな (mana-), 力 → ちから (chikara), 国 → くに (kuni)

Patterns & Rules

The actual useful part. These patterns don’t cover every case (Japanese will always find a way to produce an exception), but they apply the majority of the time and will get you to the right reading more often than guessing blindly.

ON’YOMI When On’yomi Tends to Appear

1. Two or More Kanji Together (Jukugo)

This is the big one. When you see two or more kanji written next to each other with no hiragana between them, on’yomi is almost always correct for all of them. This applies to the vast majority of compound nouns you’ll encounter.

電車 (densha): train | 図書館 (toshokan): library | 東京 (Tōkyō): Tokyo | 日本語 (nihongo): Japanese language | 勉強 (benkyō): study

2. Numbers and Counters

When kanji numbers appear with counters (units of measurement), on’yomi dominates, though there are notable exceptions with 日 (date counters) and 人 (person counter), which have kun’yomi for small numbers.

三冊 (sansatsu): three books | 六時 (rokuji): six o’clock | 百円 (hyakuen): 100 yen

3. Formal and Technical Vocabulary

Formal language, academic terms, and specialized vocabulary tend to be Sino-Japanese compounds and use on’yomi throughout. When you’re reading a newspaper, a legal document, or a medical text, on’yomi is handling most of the heavy lifting.

経済 (keizai): economy | 環境 (kankyō): environment | 医療 (iryō): medical care

KUN’YOMI When Kun’yomi Tends to Appear

1. Kanji Followed by Okurigana

This is the clearest signal in the entire system. When hiragana follow immediately after a kanji as part of the same word (not as a particle, but as the word’s grammatical ending), you’re looking at kun’yomi. Verbs and adjectives work this way almost without exception.

食べる (taberu): to eat | 書く (kaku): to write | 高い (takai): tall, expensive | 見る (miru): to see

2. A Single Kanji Standing Alone as a Word

When a single kanji functions as a complete noun on its own, without combining with other kanji, kun’yomi is the more likely reading. The kanji is being used directly as the native Japanese word for that concept.

木 (ki): tree | 火 (hi): fire | 水 (mizu): water | 空 (sora): sky | 山 (yama): mountain

3. Everyday Conversational Words

When the same concept has both a Sino-Japanese compound form and a native Japanese form, the native form is typically kun’yomi. Words for family members in casual speech, basic actions, and natural phenomena tend to be kun’yomi.

手 (te): hand | 目 (me): eye | 雨 (ame): rain | 花 (hana): flower | 道 (michi): road, path

Mixed Readings: When Both Show Up in One Word

Then there are the genuinely weird cases. Some compound words mix on’yomi and kun’yomi in a single word. These have names.

湯桶読み (Yutōyomi)

Kun’yomi first, on’yomi second. Named after the word 湯桶 (yutō) itself, which follows this pattern.

Examples: 場合 (baai): ba (on) + ai (kun) → occasion; 手本 (tehon): te (kun) + hon (on) → model, example

重箱読み (Jūbakoyomi)

On’yomi first, kun’yomi second. Named after 重箱 (jūbako), a layered box, which follows this pattern.

Examples: 台所 (daidokoro): dai (on) + tokoro (kun) → kitchen; 組合 (kumiai): kumi (kun) + ai (kun) → actually both kun here

You don’t need to memorize these terms. They exist mostly to explain why certain common words don’t follow the main patterns. When you encounter one of these words, the only reliable approach is to recognize it as a vocabulary item rather than try to derive it from rules.

Worked Examples

Abstract rules are easier to use once you’ve watched them applied to specific characters. Here are five common kanji walked through both reading types with real-world examples.

山

mountain

ON: サン (san)KUN: やま (yama)

On’yomi in use

富士山 (Fujisan): Mount Fuji

火山 (kazan): volcano

登山 (tozan): mountain climbing

Kun’yomi in use

山 (yama): a mountain

山道 (yamamichi): mountain path

山登り (yamanobori): hiking

人

person, people

ON: ジン / ニン (jin / nin)KUN: ひと (hito)

On’yomi in use

日本人 (nihonjin): Japanese person

When One Kanji Has Many Readings

Some kanji have been borrowed multiple times from different Chinese dialects at different historical periods, and they’ve picked up multiple on’yomi as a result. Others have multiple kun’yomi because the same character was mapped to several related Japanese words over time. And then there’s 生, which is more or less its own disaster.

生: A Kanji With Many Lives

Multiple on’yomi, multiple kun’yomi, and readings for names you just have to accept

On’yomi

セイ (sei): 先生 (sensei), 学生 (gakusei)

ショウ (shō): 誕生 (tanjō), 一生 (isshō)

Kun’yomi

い (i-): 生きる (ikiru, to live)

う (u-): 生まれる (umareru, to be born)

なま (nama): 生ビール (nama biiru, draft beer)

き (ki-): 生地 (kiji, fabric)

Name readings

お (o), いく (iku), ふ (fu), はる (haru), みき (miki)...

Japanese names using 生 can be read in over a dozen different ways. There is no reliable pattern.

生 has the most commonly listed readings of any kanji in the jōyō list. Context resolves most of them, but names are fair game for any pronunciation.

The important takeaway from kanji like 生 is that memorizing all possible readings in the abstract is not the goal. The goal is to learn words. When you know 先生 (sensei), you know that 生 reads as sei in that word. When you know 生ビール (nama biiru), you know 生 reads as nama there. Each word is its own unit. The list of possible readings is reference material, not a study target.

The Compound Context Rule

When you encounter an unfamiliar word that combines a kanji you know with a new kanji, you have some useful information: if both kanji appear without okurigana, try on’yomi for both. You’ll be right a majority of the time. If okurigana appear, use kun’yomi for the kanji they’re attached to. Neither rule is absolute, but both are better than guessing randomly.

How to Actually Learn Them

Knowing the difference between on’yomi and kun’yomi is useful. Here’s how to translate that into an actual study approach.

Learn Words, Not Isolated Readings

The biggest mistake new learners make is trying to memorize every possible reading for each kanji before using them in words. This is the wrong order of operations. Instead, learn vocabulary, real words you’ll encounter in Japanese, and let the readings reveal themselves through repetition. When you know 電車 (densha) and 電話 (denwa), you know that 電 reads as den in compounds. That sticks better than a flashcard listing “電: デン (den), テン (ten).”

This is also why immersive reading matters so much for kanji: encountering a character in multiple real contexts, across multiple sentences, is what actually anchors its readings in memory, not reviewing them in isolation.

Use the Patterns Actively When Reading

The rules aren’t just abstract knowledge; use them as live tools when you encounter unfamiliar text. Before looking up a word, make a prediction: is there okurigana? Then try kun’yomi. Is it a bare compound? Try on’yomi. Check if you were right. This active prediction habit builds pattern recognition faster than passive memorization, and it makes reading practice more cognitively engaging.

Practical workflow: When you see an unfamiliar word in something you’re reading, pause for a second, look at its structure, and guess the reading type before reaching for the dictionary. Even wrong guesses are useful; they highlight exactly where your intuition is miscalibrated.

Group Words by Kanji, Not by Reading Type

When studying a new kanji, learn at least one clear on’yomi example word and one clear kun’yomi example word together. For 山: learn 火山 (kazan, volcano) for on’yomi, and 山道 (yamamichi, mountain path) for kun’yomi. Concrete paired examples do more for reading intuition than abstract reading lists. The contrast makes both readings more memorable.

If you use Anki or another SRS, tag words explicitly with “on” or “kun” rather than leaving the distinction implicit. When you review them, notice which reading type you’re working with. That meta-awareness builds over time.

Accept That Some Words Are Just Exceptions

The patterns described here cover the majority of cases, but they’re not laws of physics. Japanese has centuries of exceptions, irregular readings, and words that simply don’t fit any rule. 今日 (kyō, today) and 今年 (kotoshi, this year) don’t follow standard compound reading patterns. 明日 can be read as ashita or myōnichi depending on formality and context. 一人 (hitori) and 二人 (futari) use irregular kun’yomi that don’t match the standard number+counter pattern.

These aren’t failures of the system; they’re vocabulary items. When you hit one, just learn it as a fixed unit and move on. Fighting every exception is a reliable way to slow yourself down.

Frequently Asked Questions

What is onyomi?

Onyomi (音読み), sometimes written on’yomi or on-yomi, is the Chinese-derived reading of a kanji character. It was borrowed from Chinese pronunciation when the character itself was adopted into Japanese, then adapted over time to fit Japanese sound patterns. Onyomi is shown in katakana in most dictionaries and appears mainly in multi-kanji compound words (jukugo) such as 電車 (densha, train).

What is kunyomi?

Kunyomi (訓読み), sometimes written kun’yomi or kun-yomi, is the native Japanese reading of a kanji character. Rather than being borrowed from Chinese, it’s the Japanese word that already existed for a concept, mapped onto the character that matched its meaning. Kunyomi is shown in hiragana in most dictionaries and typically appears in standalone words, verbs, and adjectives, often with hiragana okurigana attached, such as 食べる (taberu, to eat).

Is onyomi Chinese?

Onyomi is Sino-Japanese, not Chinese itself. It originated as a borrowed approximation of Chinese pronunciation, imported into Japan alongside the kanji characters between roughly the 5th and 9th centuries. Because it arrived in waves from different Chinese dialects at different points in history, modern onyomi often sounds quite different from any reading used in Chinese today, and a single kanji can have more than one onyomi as a result.

Is onyomi or kunyomi more common?

It depends on what you’re reading. Onyomi is more common overall in written Japanese because the majority of kanji vocabulary consists of two-or-more-kanji compound words (jukugo), and jukugo overwhelmingly use onyomi. Kunyomi is more common in everyday spoken Japanese, since it covers most standalone nouns, verbs, and adjectives. Readers who focus on news, academic text, or manga will lean on onyomi more; conversational learners will use kunyomi more.

Is onyomi written in katakana?

In dictionaries and reference materials, yes: onyomi is conventionally printed in katakana, while kunyomi is printed in hiragana. This is a formatting convention to make the two reading types easy to tell apart at a glance, not a rule about how the words are written in ordinary sentences. In normal writing, both onyomi and kunyomi words are usually written with the kanji itself, plus any hiragana okurigana the word needs.

Do I need to learn both readings for every kanji?

Not necessarily at the same time. Most learning approaches suggest focusing on the readings that appear in the words you’re actually studying rather than exhaustively drilling every possible reading in advance. For common kanji like 日, 人, and 山, you’ll encounter both reading types naturally through vocabulary. For rarer kanji, one reading might be all you ever need.

How do I know which reading to use if context isn’t obvious?

Start with the structural cues: okurigana present = kun’yomi; bare compound = try on’yomi. If those don’t resolve it, check whether the word is a common noun (likely on’yomi) or an adjective or verb (likely kun’yomi). When all else fails, look it up. The patterns reduce guessing; they don’t eliminate it.

Why can the same word sometimes be read two different ways?

Japanese frequently has both a native-Japanese (kun’yomi) version and a Sino-Japanese (on’yomi) version of the same concept. 今日 can be read as kyō (casual, single-word) or honjitsu (formal compound). 大人 is typically read as otona (adult, conversational) but technically 大 can be on’yomi dai. These dual readings often carry different registers or connotations, and learning which word fits which context is just a matter of exposure.

Are on’yomi or kun’yomi more important to learn first?

Neither, really, because both appear constantly in everyday Japanese. What matters is the vocabulary you’re aiming at. If you’re prioritizing reading (news, books, manga), the sheer number of jukugo means you’ll be spending more time with on’yomi. If you’re prioritizing conversation and everyday speech, kun’yomi appear more often in standalone words and verbs. Most learners end up working with both from very early on, regardless of what they intend.

How many readings can a single kanji have?

For most common kanji, one or two on’yomi and one or two kun’yomi is typical. High-frequency characters with long histories (like 生 and 行) can have four or more total listed readings. When you include name readings (nanori), the numbers grow further, but nanori readings are generally only encountered in names and don’t affect standard reading comprehension much.

Will I ever stop needing to look things up?

Eventually, yes, for most common vocabulary. Native readers encounter unfamiliar kanji compounds occasionally and simply read around them or look them up. Fluency in Japanese reading doesn’t mean being able to read every kanji cold; it means having enough vocabulary and pattern recognition that most text is accessible without a dictionary. That level takes years to build, but it does build.

Conclusion

On’yomi and kun’yomi aren’t arbitrary chaos. They’re the two main layers of a writing system that’s been accommodating two linguistic traditions simultaneously for over a thousand years. The rules aren’t perfect, but they’re real, and once you internalize the big ones (jukugo = on’yomi, okurigana = kun’yomi, standalone noun = kun’yomi), you’ll find yourself guessing correctly more often than not.

The exceptions will still trip you up sometimes. 今日 will read as kyō when you expected something else. A name will be completely unpredictable. A compound word will break every rule it could possibly break. That’s just Japanese, and no amount of studying the theory prevents it entirely.

Final Thoughts

The people who get comfortable with kanji readings are mostly the ones who do a lot of reading, not the ones who spent the most time on reading-type drills. The patterns here are useful scaffolding, not a substitute for volume. Get the framework, then go use it on actual Japanese. That’s still going to be the slightly uncomfortable part, but at least now you know why 山 has so many readings.