Who is this man in the cover page of One Piece chapter 839? In the cover page of chapter 839 of One Piece, there's a man on large bounty poster that Luffy draw number 3 on his face.


  


It seems that all Mugiwara crew give some respect to this man, even
Chopper looks like he's crying for him.

I don't think he is the character on One Piece, is this some kind of tribute from Oda to someone? So, who is he?
He is Kankichi Ryotsu from Kochikame.