Aka to Kuro
Red and Black·赤と黒
Yukio, the son of the second-in-command of the Bidou Yakuza group, is told by Yamato, the boss's son, that the boss is dying. Despite Yamato being a high school student, he is determined to take over the group. Yukio becomes infatuated with him, and the two unofficially exchange sakazuki. They believe their bond will last forever, but...