Kanji radicals: the parts inside every kanji

A kanji radical, 部首 (bushu) in Japanese, is the part of a kanji that a dictionary files it under. There are 214 traditional radicals, called the Kangxi radicals after a Chinese dictionary of 1716, and each kanji is listed under one of them: 休, the kanji in 休む (yasumu), to rest, is filed under 亻, person. Learners also say “radical” for any building block of a kanji, like the 木, tree, on the right of 休. Both uses are common, and the difference matters only now and then, mostly when you look a kanji up.

What a radical is, and what it isn’t

部首 means “section head”. A kanji dictionary is divided into sections, one for each radical, and every kanji sits in one of them. The radical is usually the part that carries the meaning: the 亻 in 休 tells you the kanji is about a person, here one leaning against a tree.

So “radical” can mean two things:

• The dictionary radical: the one part a kanji is filed under. 休 has one, 亻.
• Any component: every building block of a kanji. 休 has two, 亻 and 木. Many learners, and many learning materials, call these radicals too.

Usually it doesn’t matter which you mean. Sometimes, though, the radical isn’t the part you’d expect. 聞, the kanji in 聞く (kiku), to hear, is mostly gate, 門, but it’s filed under 耳, the ear inside. 字 (ji), a written character, as in 漢字 (kanji), has a roof on top but is filed under 子, child, the part that gives its sound. Dictionaries don’t always agree, either: one kanji can sit under different radicals in different dictionaries, especially kanji with simplified Japanese shapes.

Where radicals sit

Japanese has a name for each place a radical can sit in a kanji. There are seven:

A radical’s name is often just the radical plus its position: きへん (kihen) is tree on the left, and あめかんむり (amekanmuri) is rain on top. The names aren’t official, so dictionaries vary a little. And some places are busier than others: radicals on the left are more common than radicals on the right, and radicals on top more common than radicals underneath.

20 common radicals

Here are twenty radicals you’ll meet again and again, each with everyday kanji filed under it. Several change shape with their position: 人 thins to 亻 on the left, 水, water, becomes three drops, 氵, and 火, fire, turns into four dots, 灬, at the bottom.

Two of them share a name: 日 and 火 are both ひへん (hihen), since each can be read ひ (hi), sun or fire. A few have lessons of their own: the shell in 買, the raindrops in 雨, the roof over 家, the gate in 開 and 閉, and one tree, two trees, three trees.

Meaning hints and sound hints

Most kanji have a part that hints at the meaning, usually the radical, and a part that hints at the sound: the on’yomi, the reading that came from Chinese. These are called phono-semantic compounds, and over 80% of Chinese characters are built this way.

Take 青 (ao), blue, whose on’yomi is sei. Put a meaning part beside it and you get a family of kanji that all read sei:

The 青 tells you how to say each one, and the meaning part tells you what it’s about: sun for clear skies, water for purity, rice for 精, which first meant polished rice, and words for asking.

What radicals can and can’t tell you

Radicals break kanji into pieces you already know: a twelve-stroke kanji like 晴 becomes sun plus 青. They let you guess: a new kanji with 氵 is probably about water, and one with 言 about words. And kanji that share a sound part often share a reading. In Chirami, you can tap a part of a kanji to see every kanji that uses it: 木 leads to 林, 森, 休 and more.

But a hint is only a hint:

• Sound hints wear out. In 海 (umi), sea, 氵 gives the meaning and 毎 (mai), every, gave the sound. The two were close in old Chinese, but in Japanese 海 is read kai.
• A sound part can look like a meaning. 問う (tou), to ask, and 聞く (kiku), to hear, both put something inside a gate, 門 (mon). The gate isn’t about gates: it’s there for its sound. 問 is read mon, as in 問題 (mondai), a question.
• Look-alikes aren’t always radicals. The four dots at the bottom of 馬 (uma), horse, look just like fire’s 灬, but they began as the horse’s feet. There’s a lesson on those four dots.

So use a radical as a clue, then check the kanji’s real meaning and learn it with a word. How to learn kanji has a simple routine for that.

How to look up a kanji by its radical

A paper kanji dictionary is arranged by radical, with the radicals in order of stroke count. To find 晴:

1. Find the radical: 日, sun.
2. Turn to the 日 section.
3. Count the strokes in the rest of the kanji. 晴 has 12 strokes and 日 takes 4, so 8 are left.
4. Look through the 日 kanji with 8 extra strokes.

Many electronic dictionaries let you search by parts instead: pick the ones you can see, such as 日 and 青, and they list the kanji that contain them. Counting strokes gets easier once you know the stroke order rules.

Common questions

How many radicals are there in kanji?

There are 214 traditional radicals, the Kangxi radicals, and most Japanese kanji dictionaries use them or a version of them. Modern Chinese dictionaries have their own lists: China’s standard for simplified characters, in use since 2009, has 201. So you may see other numbers, but 214 is the usual answer.

Do I need to learn all 214 radicals?

No. Not all of them are used in modern Japanese, and some head only a handful of characters. In the Kangxi Dictionary, the grass radical heads 1,902 characters and 艮 just five. Learn the common ones, like the twenty above, as you meet them in real kanji.

What’s the difference between a radical and a component?

A component is any part of a kanji. The radical is the one component a dictionary files the kanji under. 休 has two components, 亻 and 木, and one radical, 亻. When learners say “radical”, they often mean component, and that’s fine until you look something up.

Is the radical always on the left?

No. It can sit on the left or the right, on top, underneath, or around the outside, in the seven positions above. The left is more common than the right, though, and the top more common than the bottom.

Do radicals tell you how to read a kanji?

Not usually. The radical mostly hints at the meaning. The sound hint, when there is one, is usually the other part, like 青 in 晴, and it only helps with the on’yomi. The kun’yomi are native Japanese words, so the parts can’t predict them: 晴 is sei in 晴天, but は (ha) in 晴れる (hareru), to clear up.

The kanji in this guide

Tap Draw it to watch the stroke order. Numbers show where each stroke starts.

Draw it

Draw it

Sources

• Wikipedia: Radical (Chinese characters)
• Wikipedia: Kangxi radical
• Wikipedia (Japanese): 部首
• HugKum (Shogakukan): the seven radical positions (Japanese)
• Kanji alive: the 214 traditional kanji radicals and their Japanese names
• Jisho (KANJIDIC2): radicals of 休 住 作 使 海 池 泳 洗 林 村 校 橋
• Jisho (KANJIDIC2): radicals of 味 名 品 問 持 指 押 拾 花 草 茶 葉 森 聞
• Jisho (KANJIDIC2): radicals of 話 語 読 明 時 晴 家 字 室 思 意 感 忙
• Jisho (KANJIDIC2): radicals of 紙 線 絵 緑 銀 鉄 鏡 針 地 場 坂 塩 姉 妹 始 好
• Jisho (KANJIDIC2): radicals of 道 近 週 送 雪 雲 電 雷 焼 灯 熱 照 開 閉 間 関
• Jisho (KANJIDIC2): radicals of 飯 飲 館 飼 買 財 貯 費 店 国 頭 客 寒
• Jisho (KANJIDIC2): radicals of 星 春 試
• Jisho (JMdict): 部首
• Wiktionary: 休 (a person leaning against a tree)
• Wiktionary: 晴 (phonetic 青)
• Wiktionary: 清 (phonetic 青)
• Wiktionary: 精 (phonetic 青, polished rice)
• Wiktionary: 請 (phonetic 青)
• Wiktionary: 問 (phonetic 門)
• Wiktionary: 馬 (the four strokes are its feet)
• Dong Chinese: 聞
• Dong Chinese: 海
• Dong Chinese: 字

Written by the Chirami team with the help of AI, then checked against JMdict, KANJIDIC2 and the sources above. How we write. Spotted a mistake? Email support@brightsmilesolutions.org.