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to go upstream; to go up (a river)
to go back (to the past or origin); to date back (to); to trace back (to); to be retroactive (to)
鮭は産卵のために川を遡った。
The salmon swam upstream to spawn.
この法律の起源は明治時代まで遡る。
The origin of this law traces back to the Meiji era.
歴史を遡ると意外な事実が見つかる。
Looking back through history, you find surprising facts.