～一方だ
keeps on -ing (one-way trend)
～一方だ（いっぽうだ）follows the dictionary form of a verb that expresses change (増える, 減る, 上がる, 悪くなる) and means the situation keeps moving in one direction only. In English it comes out as “keeps on -ing” or “just keeps getting ...”.
一方 literally means “one side / one direction”, so the pattern paints a trend with no reversal in sight. The similar ～ばかりだ is used only for changes the speaker sees as bad, while ～一方だ focuses on the one-way nature of the trend itself.
1. Describing a one-way trend
State the changing thing as the topic, then attach 一方だ to the verb of change.
物価は上がる一方だ。
“Prices just keep going up.”
- 物価（ぶっか）= prices (cost of goods)
- は = topic marker
- 上がる一方だ（あがるいっぽうだ）= just keeps going up
2. With ～なる for worsening states
It combines naturally with ～くなる / ～になる to complain that a state keeps intensifying.
最近、仕事は忙しくなる一方だ。
“Lately, work just keeps getting busier.”
- 最近（さいきん）= lately, recently
- 仕事（しごと）= work
- は = topic marker
- 忙しくなる一方だ（いそがしくなるいっぽうだ）= keeps getting busier
How to form it
Verb dictionary form (a verb of change) + 一方だ
- 増える（ふえる）= to increase → 増える一方だ（ふえるいっぽうだ）= keeps increasing
- 減る（へる）= to decrease → 減る一方だ（へるいっぽうだ）= keeps decreasing
- 悪くなる（わるくなる）= to get worse → 悪くなる一方だ（わるくなるいっぽうだ）= keeps getting worse
Key idea
～一方だ draws an arrow pointing one way: the change only ever goes in that direction, with no sign of stopping or turning around.
Built on the same stem
Updated .