〜一方だ
ippou da
By Nihongo PathUpdated
This form is also taught at JLPT N3, where it carries a different sense or register.
Meaning
keeps on -ing, continues to (change in one direction)
〜一方だ means "keeps on -ing" or "only continues to…". It follows a verb of change (増える, 減る, 悪くなる) and says the change goes in one direction only, without stopping. The speaker usually finds this worrying.
Both registers; common in news, reports and everyday complaints (物価は上がる一方だ). It needs a verb that expresses change, and the trend is typically undesirable. For a good trend people often use 〜ばかりだ less and 〜つつある or ますます instead.
Formation
V = verb, N = noun, A = adjective.
Vる + 一方だ
Visual diagram
上がっている
Currently rising (neutral progressive).
上がりつつある
Gradually in the process of rising (formal, neutral).
上がる一方だ
Just keeps rising with no sign of stopping (worrying trend).
上がっている
Currently rising (neutral progressive).
上がりつつある
Gradually in the process of rising (formal, neutral).
上がる一方だ
Just keeps rising with no sign of stopping (worrying trend).
Natural examples
物価は上がる一方だ。
ぶっかはあがるいっぽうだ。
Prices just keep going up.
Vる + 一方だ with a verb of change.
祖父の病状は悪くなる一方だった。
そふのびょうじょうはわるくなるいっぽうだった。
My grandfather's condition only kept getting worse.
Past tense 一方だった for a trend in the past.
仕事が増える一方で、休む暇もない。
しごとがふえるいっぽうで、やすむひまもない。
Work keeps piling up and I have no time to rest.
一方で here connects a trend to its consequence.
都市の人口は増える一方で、地方は過疎化が進んでいる。
としのじんこうはふえるいっぽうで、ちほうはかそかがすすんでいる。
City populations keep growing, while rural depopulation continues.
Note the contrast with 一方で ("on the other hand", lesson 5).
スマホばかり見ていると、視力は悪くなる一方ですよ。
スマホばかりみていると、しりょくはわるくなるいっぽうですよ。
If you keep staring at your phone, your eyesight will only get worse.
A warning in polite speech.
Similar grammar and the difference
〜ばかりだ
Nearly identical, "only gets worse", and even more clearly limited to undesirable trends.
Neutral "is in the process of"; no feeling of runaway change. Compare side by side
Different pattern: "on the one hand… on the other", a contrast between two sides. Compare side by side
Common mistakes
- ✗
- 物価は高い一方だ。
- ✓
- 物価は上がる一方だ。
- Why
- 一方だ needs a verb of change, not an adjective or a stative verb.
- ✗
- 毎日勉強しているので、成績は上がる一方だ。（意図: good news）
- ✓
- 毎日勉強しているので、成績はどんどん上がっている。
- Why
- 一方だ sounds like a worrying, uncontrolled trend; for good news use どんどん〜ている or ますます.
- ✗
- 祖父の病気は悪くなった一方だ。
- ✓
- 祖父の病気は悪くなる一方だ。
- Why
- Always dictionary form before 一方だ; put tense on だ (一方だった).
Modifies nouns as 一方の: 増える一方の借金. Often preceded by ますます or どんどん for emphasis. Typical verbs: 増える, 減る, 上がる, 下がる, 悪くなる, ひどくなる, 広がる.
JLPT N2 tips
On the exam
- Look for a verb of change in dictionary form before the blank plus a negative tone: choose 一方だ.
- Distractors are 一方で (contrast), ばかりだ, and つつある. If two contrasting clauses appear, it is 一方で, not 一方だ.
- When 一方 appears in 並べ替え, check whether だ / だった ends the sentence (trend) or で continues it (contrast).
Frequently asked questions
What does 〜一方だ mean?
keeps on -ing, continues to (change in one direction). 〜一方だ means "keeps on -ing" or "only continues to…". It follows a verb of change (増える, 減る, 悪くなる) and says the change goes in one direction only, without stopping. The speaker usually finds this worrying.
How do you form 〜一方だ?
Vる + 一方だ. V = verb, N = noun, A = adjective.
When is 〜一方だ used?
Both registers; common in news, reports and everyday complaints (物価は上がる一方だ). It needs a verb that expresses change, and the trend is typically undesirable. For a good trend people often use 〜ばかりだ less and 〜つつある or ますます instead.
What is the difference between 〜一方だ and 〜ばかりだ?
Nearly identical, "only gets worse", and even more clearly limited to undesirable trends.
What is the difference between 〜一方だ and 〜つつある?
Neutral "is in the process of"; no feeling of runaway change.
What is a common mistake with 〜一方だ?
Wrong: 物価は高い一方だ。 Right: 物価は上がる一方だ。 一方だ needs a verb of change, not an adjective or a stative verb.
Quick check
この町の人口は減る（ ）だ。