Meaning
The kanji 減 carries the core meaning of decrease, reduction, or diminishment — the act of something becoming less in quantity, size, intensity, or degree. It works as an intransitive verb meaning "to decrease on its own" (水が減る — the water decreases) and as a transitive verb meaning "to cause something to decrease" (水を減らす — to reduce the water). Keeping these two uses distinct will serve you well in natural Japanese.
Structurally, 減 is composed of two parts: the left-side radical 氵 (さんずい, the three-stroke water radical), and the right-side component 咸 (カン), which historically conveyed a sense of "all" or "encompassing," and also carries connotations of saltiness and erosion. The combination evokes the image of water gradually diminishing — like a river wearing away or a reservoir slowly draining. Once you see the parts, the character's meaning clicks into place.
The kanji is classified at Grade 5 elementary school level in Japan, meaning Japanese children learn it around age 10–11. It has 12 strokes and belongs to the water radical group (氵部). At JLPT N3, 減 turns up regularly in news, business writing, and everyday conversation — especially in discussions about economics, health, and the environment. Learning it opens the door to a broad set of useful compound words.
Conceptually, 減 stands in direct contrast to 増 (increase). The pairing 増減 (increase and decrease) is one of the most common compounds in Japanese. It appears in financial reports, scientific studies, and casual speech alike.
Readings
On'yomi (音読み) — Chinese-derived readings
The on'yomi of 減 is ゲン (GEN). This reading appears almost exclusively in compound words (熟語, jukugo) with other kanji, and it dominates formal, written, and academic Japanese. ゲン connects a large family of useful vocabulary.
- 減少 (genshō) — decrease, decline (e.g., population decline)
- 削減 (sakugen) — cutback, reduction (e.g., budget cuts)
- 増減 (zōgen) — increase and decrease, fluctuation
- 軽減 (keigen) — mitigation, alleviation (e.g., reducing burden)
- 半減 (hangen) — reduction by half, halving
- 減速 (gensoku) — deceleration, slowing down
- 減量 (genryō) — weight reduction, reducing quantity
- 減税 (genzei) — tax reduction, tax cut
- 減点 (genten) — point deduction, penalty points
Kun'yomi (訓読み) — Native Japanese readings
The kun'yomi readings of 減 are へ.る (he.ru) and へ.らす (he.rasu). The dot notation shows where the kanji reading ends and the okurigana begins. These readings carry the verb forms used in everyday speech.
へ.る is an intransitive verb (自動詞) — the subject decreases by itself, without an agent acting upon it. Example: 体重が減った (My weight decreased).
へ.らす is a transitive verb (他動詞) — the subject actively reduces something. Example: 食事の量を減らす (to reduce the amount of food eaten).
- 減る (heru) — to decrease, to diminish (intransitive)
- 減らす (herasu) — to reduce, to cut down (transitive)
Common Words & Compounds
Below are key vocabulary items using 減, grouped by theme.
Economy & Finance
- 削減 (sakugen) — budget cut, cost reduction
- 減税 (genzei) — tax reduction
- 減収 (genshū) — decrease in income/revenue
- 節減 (setsugen) — economizing, cost-saving
Health & Body
- 減量 (genryō) — weight loss, reducing quantity
- 体重が減る (taijū ga heru) — to lose weight
- 軽減 (keigen) — alleviation of pain or burden
- 減塩 (gen'en) — low-sodium, salt reduction
General & Academic
- 減少 (genshō) — decrease, decline
- 増減 (zōgen) — fluctuation, ups and downs
- 半減 (hangen) — halving, 50% reduction
- 減速 (gensoku) — deceleration, slowing down
- 減点 (genten) — point deduction, demerit
- 加減 (kagen) — adjustment, moderation; also used for how one feels (お加減はいかがですか — How are you feeling?)
Example Sentences
最近、体重が少し減った。
Saikin, taijū ga sukoshi hetta.
Recently, my weight has decreased a little.
食事の量を減らすようにしています。
Shokuji no ryō wo herasu yō ni shite imasu.
I am trying to reduce the amount I eat.
日本では人口が減少しています。
Nihon de wa jinkō ga genshō shite imasu.
Japan's population is declining.
政府は税金を減らすことを約束した。
Seifu wa zeikin wo herasu koto wo yakusoku shita.
The government promised to reduce taxes.
残業を削減するための新しいルールができた。
Zangyō wo sakugen suru tame no atarashii rūru ga dekita.
A new rule was established to cut down on overtime work.
車は交差点の前で減速した。
Kuruma wa kōsaten no mae de gensoku shita.
The car slowed down before the intersection.
塩分を減らした食事が健康にいいと言われています。
Enbun wo herashita shokuji ga kenkō ni ii to iwarete imasu.
It is said that a diet with reduced salt is good for your health.
この工場では、CO2の排出量を半減させることが目標です。
Kono kōjō de wa, CO2 no haishutsuryō wo hangen saseru koto ga mokuhyō desu.
The goal at this factory is to halve CO2 emissions.
試験で誤字があると減点されます。
Shiken de goji ga aru to genten saremasu.
If there are spelling mistakes on the exam, points will be deducted.
在庫が増減を繰り返しているため、管理が難しい。
Zaiko ga zōgen wo kurikaeshite iru tame, kanri ga muzukashii.
Because the inventory keeps fluctuating up and down, it is difficult to manage.
Memory Tip
Picture a river (氵, the water radical) slowly running dry. You watch the water level creep lower and lower — 減っていく (decreasing).
The right side of the kanji, 咸, has an old meaning tied to salt and erosion. Imagine the riverbank being eaten away by saltwater, land and water both shrinking over time. Put the two together — 氵 + 咸 = 減 — and the image holds: water wearing something away, making it less.
For the on'yomi, pair ゲン with the English word "gone" — something has gone, it has decreased. And for the kun reading, へ sounds like a small sigh: へ～, your wallet got lighter again.