一方（いっぽう）だ (ippou da)
～一方だ — keeps ～ing in one direction
Pattern
-
V辞書形＋一方だDictionary form + 一方だ
Meaning and connection
一方 means one direction. ～一方だ says nothing else changes and the situation only moves that way. It attaches to verbs of change such as 上がる, 増える, 減る, 悪くなる, 広がる.
When to use
Fits written or formal descriptions of prices, population, illness or workload. It is close to ～ばかりだ. Do not confuse it with その一方で (on the other hand), a different use of 一方.
Examples
-
物価（ぶっか）は上（あ）がる一方（いっぽう）だ。
Bukka wa agaru ippō da.
Prices keep going up and up.
-
都会（とかい）の人口（じんこう）は増（ふ）える一方（いっぽう）だ。
Tokai no jinkō wa fueru ippō da.
The city's population just keeps increasing.
-
祖母（そぼ）の病気（びょうき）は悪（わる）くなる一方（いっぽう）だ。
Sobo no byōki wa waruku naru ippō da.
My grandmother's illness just keeps getting worse.
Common mistakes
- Use it with verbs of change. 食べる一方だ is odd because eating is not a change.
- It is different from 一方で, which contrasts two sides.
More grammar points
- ばよかった ～ばよかった — I should have ～, if only I had ～
- ばかりで ～ばかりで — only ～ (and nothing else, with a negative feeling)
- ばかりでなく ～ばかりでなく — not only ～ but also ～
- だけでなく ～だけでなく — not only ～ but also ～
- だけど だけど — but, however (casual)
- ふりをする ～ふりをする — pretending to ～
- 一体（いったい） 一体 — what on earth ～ (emphasizing a question)
- じゃない ～じゃない — isn't it ～! (surprise or confirmation)
- か何（なに）か ～か何か — ～ or something
- 代（か）わりに ～代わりに — instead of ～, in return for ～
- 結局（けっきょく） 結局 — in the end, after all
- きり ～きり — only ～; ever since ～
- っけ ～っけ — was it ～? (recalling)
- ことになっている ～ことになっている — it is the rule or plan that ～
- ことは～が ～ことは～が — it is true that ～, but ～
- くせに ～くせに — even though ～ (with reproach)
- も～ば～も A も ～ば B も ～ — both A and B
- むしろ むしろ — rather, if anything
Practice this in the app
Mainichi JLPT turns these grammar points into daily quizzes and a readiness gauge — 100% free, no sign-up.