expression
as soon as; right after; no sooner than
Used after a verb to indicate that something happens immediately after the action, often with a nuance of repetition or that the result is undone quickly. Common in patterns like V-ru + そばから or V-ta + そばから.
覚えるそばから忘れてしまう。
I forget things as soon as I learn them.
片付けるそばから子供が散らかす。
The kids make a mess right after I tidy up.
とたん (途端) also means 'just as' or 'the moment', but it emphasizes a sudden change or event at that exact instant, while そばから often implies a repeated or immediate undoing of the previous action.
次第 means 'as soon as' and is used in formal or business contexts to indicate that something will be done immediately after a condition is met, without the repetitive or negative nuance of そばから.
Derived from そば (side, vicinity) + から (from). The temporal meaning 'as soon as' developed from the spatial sense of 'from the side', implying an action happening immediately alongside another.