〜一方だ / 〜いっぽうだ
ippou da
By Nihongo PathUpdated
This form is also taught at JLPT N2, where it carries a different sense or register.
Meaning
keeps on …ing / continues only to… (one-directional change)
〜一方だ says a change goes in one direction only and does not stop: 物価は上がる一方だ "prices just keep rising". It attaches to verbs of change (増える, 減る, 上がる, 悪くなる). The tone is often worried, but unlike 〜ばかりだ it can also describe a neutral or positive trend.
News, essays, business reports and everyday complaints about trends: 仕事が増える一方だ. Do not confuse it with 〜一方(で) "on the other hand", which links two clauses.
Formation
V = verb, N = noun, A = adjective.
Verb (dictionary form, change verb) + 一方だ / 一方ですPast: 〜一方だったConnective: 〜一方で (also 'keeps increasing, and…')
Visual diagram
| Aspect | Direction | Tone | Example |
|---|---|---|---|
| 〜一方だ | One way only, no stopping | Neutral or worried | 物価は上がる一方だ |
| 〜ばかりだ | One way only, getting worse | Negative only | 成績は下がるばかりだ |
| 〜てきた | Change up to now | Neutral | 物価が上がってきた |
Natural examples
物価は上がる一方だ。
ぶっかはあがるいっぽうだ。
Prices keep on rising.
Prices keep going up; no sign of stopping.
父の病気は悪くなる一方だった。
ちちのびょうきはわるくなるいっぽうだった。
My father's illness just kept getting worse.
Past: 一方だった.
仕事が増える一方で、休む暇がない。
しごとがふえるいっぽうで、やすむひまがない。
Work keeps increasing and I have no time to rest.
一方で connective: the trend plus its consequence.
この会社の業績は、ここ数年伸びる一方だ。
このかいしゃのぎょうせきは、ここすうねんのびるいっぽうだ。
This company's results have done nothing but grow these past few years.
A positive trend: possible with 一方だ but not with ばかりだ.
スマートフォンの利用時間は長くなる一方です。
スマートフォンのりようじかんはながくなるいっぽうです。
Time spent on smartphones just keeps getting longer.
Adjective + なる + 一方だ.
Similar grammar and the difference
Same structure but only for things getting worse. Compare side by side
'On the other hand' — links two contrasting clauses. Different meaning, same kanji. Compare side by side
Show direction in time but not the 'never stops' emphasis. Compare side by side
Common mistakes
- ✗
- 物価は上がった一方だ。
- ✓
- 物価は上がる一方だ。
- Why
- 一方だ takes the dictionary form; the past goes on だ (一方だった).
- ✗
- 彼は勉強する一方だ。
- ✓
- 彼は勉強ばかりしている。
- Why
- 一方だ needs a verb of change (increase, decrease, worsen). 勉強する is an action, not a change.
- ✗
- 都会は便利な一方だ。
- ✓
- 都会は便利になる一方だ。
- Why
- An adjective must be turned into a change with なる before 一方だ.
Frequent partners: 増える, 減る, 上がる, 下がる, 悪くなる, 高くなる, ひどくなる. Sentence-initial 一方、 and clause-linking 一方で are the contrast meaning; sentence-final 一方だ is the trend meaning. In formal writing: 〜一方である.
JLPT N3 tips
On the exam
- If the blank ends the sentence and the verb is about change, 一方だ is likely; if a second clause follows with a different subject, it is 一方で.
- If the trend is positive (伸びる, よくなる), only 一方だ works, not ばかりだ.
- Check the verb form: dictionary form only.
Frequently asked questions
What does 〜一方だ / 〜いっぽうだ mean?
keeps on …ing / continues only to… (one-directional change). 〜一方だ says a change goes in one direction only and does not stop: 物価は上がる一方だ "prices just keep rising". It attaches to verbs of change (増える, 減る, 上がる, 悪くなる). The tone is often worried, but unlike 〜ばかりだ it can also describe a neutral or positive trend.
How do you form 〜一方だ / 〜いっぽうだ?
Verb (dictionary form, change verb) + 一方だ / 一方です / Past: 〜一方だった / Connective: 〜一方で (also 'keeps increasing, and…'). V = verb, N = noun, A = adjective.
When is 〜一方だ / 〜いっぽうだ used?
News, essays, business reports and everyday complaints about trends: 仕事が増える一方だ. Do not confuse it with 〜一方(で) "on the other hand", which links two clauses.
What is the difference between 〜一方だ / 〜いっぽうだ and 〜ばかりだ?
Same structure but only for things getting worse.
What is the difference between 〜一方だ / 〜いっぽうだ and 〜一方(で)?
'On the other hand' — links two contrasting clauses. Different meaning, same kanji.
What is a common mistake with 〜一方だ / 〜いっぽうだ?
Wrong: 物価は上がった一方だ。 Right: 物価は上がる一方だ。 一方だ takes the dictionary form; the past goes on だ (一方だった).
Quick check
運動をやめてから、体重は（ ）一方だ。