一方（だ） (da)

Meaning & usage

一方だ (いっぽうだ) describes a change that keeps moving in one direction. Use it after the dictionary form of a verb of change, such as 増える (increase) or 減る (decrease). It can describe an ongoing trend rather than a single completed event.

To describe a changing adjective, use a verb form such as 高くなる一方だ (keeps getting more expensive), rather than attaching 一方だ directly to 高い. The polite ending is 一方です.

Keep this pattern separate from 一方で (on the other hand), which contrasts two aspects of a situation. The noun 一方 in 一方通行 (one-way traffic) also does not demonstrate this grammar pattern.

Example sentences 3

1. 使つかわないアプリが増ふえる一方いっぽうだ。

   The number of apps I do not use keeps increasing.

2. この店みせの客きゃくは減へる一方いっぽうです。

   The number of customers at this shop keeps decreasing.

3. 修理しゅうりを待まつ間あいだに、問題もんだいは大おおきくなる一方いっぽうだった。

   While we waited for repairs, the problem kept getting bigger.

Words in these examples

• 増える (ふえる): to increase
• 減る (へる): to decrease (in size or number),to diminish,to abate

Sources and content notes

• MLC Japanese Language School: 一方だ・ばかりだ

This explanation and the original examples were corrected with AI assistance. Independent Japanese-language review is pending.