expression, adverb
Describes doing or processing things sequentially, emphasizing a steady, step-by-step progression. Often used with verbs like 片付ける, 消える, 増える, etc.
彼は問題を一つまた一つと解決していった。
He solved the problems one by one.
星が一つまた一つと消えていった。
The stars disappeared one after another.
一つずつ also means 'one by one' but focuses on distributing or doing things individually, often with a sense of fairness or careful allocation. 一つまた一つ emphasizes a sequential, accumulating process.
次々に means 'one after another' in rapid succession, without the step-by-step nuance of 一つまた一つ.
A fixed expression composed of 一つ (one) + また (again) + 一つ (one), literally 'one, and again one'. The repetition emphasizes sequential occurrence.