Yagyu Jubei and the eye

In pop fiction, Yagyu Jubei is usually depicted as being blind in one eye.  And many people believe this is true for him in real life.  And maybe he did at some point lose the use of one eye.  Howver, there is one print of him that exists, and that print portrays him having two eyes, so the debate continues.

That said, the origin is usually attributed to his father accidentally blinding him during a sparring session using real swords.  In my novella, it happens resulting from a duel with Kageura.  In short, there are as many different variations of the origin as there are fictionalized accounts of Jubei.

Here is one from an anime. The end of the clip has a summary of other historical samurais who have become legends.