必ずしも【かならずしも】

必ずしも (not always, not necessarily, not entirely) is an adverb used to soften or negate absolute statements. It expresses the idea that something is not universally or inevitably true – there are exceptions. It is always paired with a negative predicate (such as 〜～ない, 〜～とはかぎらない限らない, etc.).

The word かならず必ず means "always" or "certainly," so 必ずしも～ない literally conveys "it is not certainly the case that…" – in other words, "not necessarily."

Common negative patterns

必ずしも frequently appears with several negative endings:

• 必ずしも～ない: the most basic pairing

  かれ彼のいう言うことはかならずしも必ずしもただしくない正しくない。

  What he says is not always correct.

• 必ずしも～とは限らない: "it is not necessarily the case that…"

  おかねお金があればかならずしも必ずしもしあわせ幸せだとはかぎらない限らない。

  Having money doesn't necessarily mean you're happy.

• 必ずしも～わけではない: "it doesn't necessarily mean that…"

  やすい安いからといって、かならずしも必ずしもしつがわるい質が悪いわけではない。

  Just because something is cheap doesn't necessarily mean the quality is bad.

Nuance

必ずしも does not mean "never" – it acknowledges that while something may often be true, it is not always or universally true. It leaves room for exceptions. Compare:

• かならず必ずせいこう成功する – will definitely succeed
• かならずしも必ずしもせいこう成功しない – won't necessarily succeed (but might)