空 — Kanji Reference

空 (sky, empty): 8 strokes, JLPT N5. On: クウ. Kun: そら、あ-く、から.

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空

Property Value
Meaning sky, empty
Strokes 8
JLPT Level N5
On-reading (音読み) クウ
Kun-reading (訓読み) そら、あ-く、から
Radical 穴 (あなかんむり - cave/hole radical, U+7A74)

Stroke Order

The kanji 空 follows the standard Japanese calligraphy rule of "top-to-bottom, left-to-right."

  1. Stroke 1: The top dot (left side of the roof).
  2. Stroke 2: The second dot (right side of the roof).
  3. Stroke 3: The top horizontal stroke of the roof.
  4. Stroke 4: The left vertical stroke of the roof.
  5. Stroke 5: The right vertical stroke of the roof.
  6. Stroke 6: The top horizontal line of the bottom component (工).
  7. Stroke 7: The vertical line of the bottom component.
  8. Stroke 8: The bottom horizontal line of the bottom component.

Radical Analysis

The main radical is 穴 (あなかんむり - ana-kanmuri), which means "cave" or "hole." The bottom part is 工 (こう - kou), which represents construction or work.

Historically, the kanji depicts a "cave" (穴) that has been "worked on" or "hollowed out" (工), leading to the concept of something being empty or a wide, open space like the sky.

Mnemonic

Imagine a cave (the radical 穴) where a construction worker (工) has cleared everything out. It is now completely empty (から). When you look up from the bottom of this empty cave, you see the vast blue sky (そら).

On-readings (音読み) with Examples

クウ (Kuu)

Word Reading Romaji English
空港 くうこう kuukou Airport
空気 くうき kuuki Air
空中 くうちゅう kuuchuu In the air
空席 くうせき kuuseki Vacant seat

Kun-readings (訓読み) with Examples

そら (Sora)

Word Reading Romaji English
青空 あおぞら aozora Blue sky
空模様 そらもよう soramoyou Weather/Sky condition

あ-く (A-ku)

Word Reading Romaji English
空く あく aku To open/become vacant
空き部屋 あきべや akibeya Vacant room

から (Kara)

Word Reading Romaji English
空っぽ からっぽ karappo Empty
空手 からて karate Karate (lit. "empty hand")

JLPT N5 Words Using 空

Word Reading Romaji English JLPT
空 そら sora Sky N5
空港 くうこう kuukou Airport N5
空気 くうき kuuki Air N5
空く あく aku To open/be empty N5
空っぽ からっぽ karappo Empty N4
空席 くうせき kuuseki Vacant seat N3
空中 くうちゅう kuuchuu Mid-air N3
空手 からて karate Karate N4

Example Sentences

Japanese Reading Romaji English
今日は空が青いです。 きょうはそらがあおいです。 Kyou wa sora ga aoi desu. The sky is blue today.
空港までタクシーで行きます。 くうこうまでタクシーでいきます。 Kuukou made takushii de ikimasu. I will go to the airport by taxi.
箱の中は空っぽです。 はこのなかはからっぽです。 Hako no naka wa karappo desu. The inside of the box is empty.
部屋が空いています。 へやがあいています。 Heya ga aite imasu. The room is vacant.
新鮮な空気を吸います。 しんせんなくうきをすいます。 Shinsen na kuuki o suimasu. I breathe in fresh air.
彼は空手が得意です。 かれはからてがとくいです。 Kare wa karate ga tokui desu. He is good at karate.

Common Confusion Pairs

Kanji Reading Meaning How to distinguish
空 そら Sky/Empty Has the "cave" radical (穴) on top.
究 きゅう Research Has the "cave" radical (穴) but "nine" (九) inside.
突 つつ Thrust Has the "cave" radical (穴) but "dog" (犬) inside.

Usage Frequency Note

空 is a high-frequency kanji used daily in both formal and informal contexts. You will encounter it constantly in travel (airport/空港), daily life (vacant seats/空席), and casual conversation (the sky/空). It is one of the first 100 kanji learned by students in Japan.