部首 (bushu), or radicals, are the building blocks of kanji. Most kanji are made by combining a radical (which often hints at meaning or category) with other parts. Learning radicals helps you recognize, guess the meaning of, and look up unfamiliar kanji and makes memorization much easier.
This lesson covers what radicals are, how they work, common radicals and their meanings, where they appear in characters, and how to use them in dictionaries and in your study.
What Are Radicals?
A radical is a recognizable component that appears inside kanji. Historically, Chinese character dictionaries grouped characters under a set of “header” components the 部首. That system is still used today: each kanji is assigned one radical (its “main” component) for dictionary lookup, and many kanji clearly break down into a radical plus other parts.
Why radicals matter
- Lookup: Paper and digital dictionaries often index kanji by radical and stroke count.
- Meaning: Many radicals suggest the theme of the character (water, person, speech, etc.).
- Recognition: Spotting the radical helps you parse and remember complex kanji.
- Spelling: Knowing common parts reduces the “random strokes” feeling and improves recall.
Meaning and Sound: 意符 and 音符
Many kanji are built from:
- Semantic component (意符): suggests meaning (e.g. “water,” “tree,” “person”).
- Phonetic component (音符): suggests sound (often the on’yomi).
The radical is usually the semantic part. For example, in 河 (river), the left part 氵 (three drops of water) is the radical and indicates “water”; the right part can hint at the reading. Not every kanji fits this pattern neatly, but the idea helps with many characters. Not every semantic component is the dictionary radical each kanji has one official radical for lookup, which may not be the part that “looks” most important to you.
| Kanji | Meaning | Radical (meaning hint) | Other part |
|---|---|---|---|
| 河 | river | 氵 (water) | 可 (phonetic: ka) |
| 語 | language, word | 言 (speech) | 吾 (phonetic: go) |
| 休 | rest | 亻 (person) | 木 (tree) → “person by tree” |
休 is a 会意文字 (associative compound): meaning + meaning (“person by tree” = rest), not a phonetic–semantic character.
Common Radicals and Their Meanings
Here are some of the most frequent radicals you’ll see. Learning these will help you guess meaning and find kanji in dictionaries.
Water (さんずい)
Three drops of water, often on the left
Examples: 河 river, 海 sea, 泳 swim
Person (にんべん)
Person radical, on the left
Examples: 人 person, 休 rest, 仕 serve
Speech (ごんべん)
Words, speech, language
Examples: 語 language, 話 talk, 説 explain
Tree (きへん)
Tree, wood
Examples: 木 tree, 林 woods, 森 forest
Fire (ひへん / れっか; れんが is a variant)
Fire, heat; 灬 as bottom form
Examples: 火 fire, 焼 burn, 熱 heat
Heart (こころ / りっしんべん)
Heart, mind, emotions
Examples: 思 think, 情 emotion, 忘 forget
See Radicals in KanjiVG
KanjiVG is a project that provides stroke data and component decomposition for thousands of kanji. Below you can see the components (visual building blocks) and the radical the dictionary-assigned radical used for lookup. That radical may differ from what you intuitively think is the “main” part of the character. Data is loaded from KanjiVG when you view this lesson.
Where Radicals Appear: 偏, 旁, 冠, 脚
Radicals have typical positions and names in Japanese. Knowing these helps when you look up a kanji or describe its shape. The names below describe component position; the part in that position is not always the dictionary radical.
| Position | Japanese | Meaning | Example |
|---|---|---|---|
| Left | 偏 | hen | 休 (亻 on left) |
| Right | 旁 | tsukuri | 河 (可 on right) |
| Top | 冠 | kanmuri ( “crown” ) | 花 (艹 on top) |
| Bottom | 脚 | ashi ( “foot” ) | 思 (心 on bottom) |
| Enclosure | 構 | kamae | 国 (囗 surrounds) |
Using Radicals to Look Up Kanji
In paper dictionaries, kanji are usually ordered by radical, then by number of extra strokes. Steps:
- Identify the radical (often left, top, or an enclosure).
- Find the radical in the radical index (often at the front).
- Note the radical’s number and go to that section.
- Within that section, find your kanji by the stroke count of the remaining part.
In digital dictionaries and apps, you can often search by radical, draw the character, or paste it. Even then, recognizing the radical helps you confirm you’ve found the right entry and understand the character’s structure.
Radical-Based Memorization
Use radicals to make kanji stick:
- Break it down: Before memorizing a kanji, name its radical and the other part (e.g. “water + this sound part”).
- Group by radical: Study several kanji that share the same radical (e.g. 言 words) to reinforce the meaning hint.
- Stories: Build a short story from the parts (e.g. 休: “a person 亻 resting by a tree 木”).
- Consistency: Some radicals change form by position (e.g. 水 → 氵 on the left). Learn those variants so you recognize them everywhere.
Quick tip
You don’t need to learn all 214 Kangxi radicals at once. Start with the dozen or so that appear in your first textbook or JLPT N5 kanji; add more as you meet new characters.
Practice what you’ve learned with the radical games flashcards and quizzes by JLPT level.
Summary
Radicals (部首) are the key components of kanji. They often carry a meaning hint, appear in predictable positions (偏, 旁, 冠, 脚, 構), and are used to look up and memorize kanji. Learning the most common radicals will make the rest of your kanji study faster and more logical.
You know what radicals are and how they help with meaning, position, and lookup.
Next up: Continue to Radicals vs Components below to see how the dictionary radical differs from stroke-path components. 頑張って！