there are no mysterious losses; defeat always has a reason
Proverb meaning that losses or failures are never without cause; one should reflect on the reasons for defeat rather than attributing it to bad luck. Often contrasted with 勝ちに不思議の勝ちあり (wins can sometimes be inexplicable).
See also: 勝ちに不思議の勝ちあり、負けに不思議の負けなし
We lost the match because we didn't practice enough. As they say, there are no mysterious losses.
The contrasting proverb: wins can sometimes come unexpectedly or without clear reason, whereas losses always have a cause.
A traditional Japanese proverb. The exact origin is uncertain, but it reflects a common cultural emphasis on self-reflection and accountability in defeat.