Name of a specific Japanese Emperor?

I only have the following details to help narrow down the search:

-There is a story where a child dropped a knife on the emperors foot, the emperor did not punish the child.

-The emperor lived between the 5th century and the 10th century AD.

-They existed either as samurais began to emerge, or before the emergence of samurais.

I've tried going on wikipedia, clicking on every single emperor article and Ctrl-F-ing the word "foot" (because the word "knife" or "child" might not be used in the article, but perhaps maybe "blade" and "kid" instead, or something like that), but I have not found anything.

As the 11th Emperor Suinin's legend,
he was almost stabbed by SahoHime-no-mikoto the empress consort.
And he never wanted to punish her.
Although it's in the mythological age...(x_x;