New Prince of Tennis
Kunikazu Tezuka is Kunimitsu Tezuka's grandfather.
His personality is quite similar to that of his grandson Kunimitsu and he seems to have a rivalry with Sanada Genichiroh's grandfather, which is similar to the rivalry between Tezuka Kunimitsu and Sanada Genichiroh: Sanada is the driving force behind the rivalry while Tezuka seems to be uninterested and ignores Sanada. Grandfather Tezuka's hobby is fishing.
Kunimitsu Tezuka - Both have a very close relationship with each other. Kunikazu would even skip his shogi game (New Prince of Tennis OVA 1) just to go fishing and spend some time with him.