Sanjiro is, like a lot of Phoenix, relatively short and lithe (even by Rokugani standards) and possessed of fair skinned with jet black hair and dark brown eyes.  With his high cheekbones and angular face, if it weren't for the soft, gentle look that seemed always present on his face, he'd likely be considered to have an extremely serious mien. His hair is fairly long, pulled into something of a messy bun just keeping it tied up to be tidy more than anything else.

It would be fair to call Sanjiro's look more rustic than anything else, except for the rather eye-catching reds and oranges that he, like most Phoenix, seems to favor.  In addition, he is never seen without an ornately carved scroll case at his side.  If he were older, it would no doubt be filled with prayers to the kami, but as it stands, it's mostly an assorted collection of histories or stories that he's found interesting and managed to somehow get his hands on.