Meaning
The kanji 循 (ジュン) means to circulate, to follow a set path, or to go around in a cycle. It covers physical movement — blood flowing through the body, water cycling through the environment — and also the more abstract idea of following rules, customs, or step-by-step procedures. You'll meet 循 most often in medical, scientific, and formal Japanese.
The kanji has two parts. On the left is 彳 (gyōninben), the "walking step" radical that signals movement or forward progress. On the right is 盾 (tate, shield), which functions as a phonetic element — giving the kanji its ジュン reading — and visually hints at something solid and structured that keeps cycling back. Picture a guard with a shield endlessly walking the same patrol route. That image sits inside 循.
循 has 12 strokes and is a high-school-level Jōyō kanji — not taught in elementary grades. It traces back to classical Chinese, where it meant to follow along or comply with. In modern Japanese, 循 rarely stands alone; it almost always pairs with other kanji. Its most important compound, 循環 (junkan), spans everything from cardiology to climate science.
Readings
On'yomi (音読み) — Chinese-derived readings
循 has one on'yomi: ジュン (JUN). Every compound built around this kanji uses that reading — formal writing, medical reports, scientific papers. Several other kanji share the same sound: 順 (order), 准 (quasi), 巡 (patrol), 盾 (shield). Confusing at first, but once you notice that the ジュン cluster tends to involve sequential movement or going around, they start to sort themselves out.
- 循環 (junkan) — circulation, cycle; the most common and important compound
- 因循 (injun) — following old customs without change; being stuck in a rut
- 循序 (junjo) — in sequential order; step by step
Kun'yomi (訓読み) — Native Japanese readings
循 has no kun'yomi. Like many N1 kanji, it was borrowed from Chinese for use in formal vocabulary, not to represent a native Japanese word. Focus entirely on ジュン and its compounds — especially 循環 and 悪循環. That covers everything you need.
Common Words & Compounds
These are the compounds you're most likely to encounter, from hospital signs to environmental policy debates:
- 循環 (junkan) — circulation, cycle; the core compound, used across medicine, science, and daily speech
- 循環器 (junkanki) — circulatory organ or system (heart, blood vessels)
- 循環器科 (junkanki-ka) — cardiology department in a hospital
- 悪循環 (akujunkan) — vicious cycle; a self-reinforcing negative loop
- 循環型社会 (junkangata shakai) — recycling-based society; circular resource use
- 循環経済 (junkan keizai) — circular economy; an economic model built on reuse and recycling
- 循環小数 (junkan shōsuu) — repeating decimal, such as 0.333...
- 循環バス (junkan basu) — loop bus; a bus that runs a fixed circular route
- 血液循環 (ketsueki junkan) — blood circulation
- 水循環 (mizu junkan) — the water cycle; the hydrological cycle
- 因循 (injun) — conservative inertia; unwillingness to change established ways
- 循序漸進 (junjo zenshin) — making gradual, steady progress step by step; used in academic and policy writing
Example Sentences
心臓は全身の血液を循環させる。
Shinzō wa zenshin no ketsueki wo junkan saseru.
The heart circulates blood throughout the entire body.
悪循環に陥らないように気をつけてください。
Akujunkan ni ochiiranai yō ni ki wo tsukete kudasai.
Be careful not to fall into a vicious cycle.
この路線バスは市内を循環している。
Kono rosen basu wa shinai wo junkan shite iru.
This bus line loops around the city center.
水は自然界で常に循環している。
Mizu wa shizenkai de tsune ni junkan shite iru.
Water circulates endlessly in the natural world.
循環器科の専門医に診てもらった。
Junkanki-ka no senmon'i ni mite moratta.
I was seen by a cardiologist.
0.333…は循環小数だ。
Zero-ten-san-san-san… wa junkan shōsuu da.
0.333... is a repeating decimal.
環境問題を解決するには循環型社会が必要だ。
Kankyō mondai wo kaiketsu suru ni wa junkangata shakai ga hitsuyō da.
A recycling-based society is essential for solving environmental problems.
因循な考え方を変えることが大切だ。
Injun na kangaekata wo kaeru koto ga taisetsu da.
Breaking free of outdated, conservative thinking is what matters.
血液が正常に循環しないと健康を害する。
Ketsueki ga seijō ni junkan shinai to kenkō wo gaisuru.
Poor blood circulation damages your health.
循環型経済への移行が世界中で議論されている。
Junkangata keizai e no ikō ga sekaijū de giron sarete iru.
The shift to a circular economy is being debated across the globe.
Memory Tip
A shield-bearer (盾) pacing along a road (彳), round and round, never stopping — that's the image locked inside 循. He walks the same patrol route every hour, every day: a perfect cycle, going nowhere but always moving. For the reading, ジュン sounds like the first syllable of "journey" — and this particular journey never ends. Shield + road + endless patrol = 循.