conjunction
so; therefore; for that reason
Dated conjunction meaning 'so' or 'therefore'. Used in formal or literary contexts; in modern Japanese, だから or それで is more common.
彼は正直者だ。さすれば、この話は真実だろう。
He is an honest person. Therefore, this story is probably true.
conjunction
if so; if that is the case; in that case
Dated conjunction meaning 'if so' or 'in that case'. Often used in hypothetical or conditional statements; modern equivalents include それなら or そうであれば.
明日雨が降るかもしれない。さすれば、遠足は中止だ。
It might rain tomorrow. If so, the excursion will be canceled.
Derived from classical Japanese 然 (sa, 'so') + すれば (sureba, conditional form of する). The exact historical development is uncertain, but it functions as a fossilized conditional expression.