河童かっぱの川かわ流ながれ

expression

anyone can make a mistake; even experts slip up

Proverb literally meaning 'a kappa swept away by a river'; used to say that even an expert can fail in their own field.

• 彼かれはベテランのプログラマーなのに、簡かん単たんなバグを見み逃のがした。まさに河童かっぱの川かわ流ながれだね。

  He's a veteran programmer, but he missed a simple bug. It's a perfect example of 'even a kappa can be swept away by a river.'