～て初(はじ)めてFor the first time, Not until, Only after, Only when, Only because

まず means 'first' or 'to begin with' and is used to express something that happens or should happen before something else. In contrast, て初めて means 'not until (A) did (B) happen' or 'for the first time after (A), (B)', e.g. 大人になって初めて分かった ('I understood for the first time after becoming an adult.').

Les deux expressions てから et て初めて expriment des actions consécutives, mais avec des nuances différentes. てから indique simplement qu'un événement se produit après un autre, tandis que て初めて met en avant que la deuxième action n'arrive « que » ou « seulement après » la première. Cette dernière expression souligne que c'est l'accomplissement de la première action qui rend possible la seconde pour la première fois.

Both show one action leading to another, but with different focus. て初めて marks a first experience or realization, e.g. 大人になって初めて分かった ('I only understood after becoming an adult.') 上で shows a necessary step before the next action, e.g. 社長に相談した上で決めましょう ('Let's decide after consulting the president.')

Both imply 'only after (A) did (B) happen', but differ in nuance. て初めて is typically used in a positive sense, often conveying realization or discovery, e.g. 大人になって初めて分かった ('I first understood after becoming an adult'). In contrast, てからでないと focuses on the negative—the inability to do something until a condition is met, e.g. パスポートを取ってからでないと申し込めない ('You can't apply unless you get a passport first').