Ryoshuu (TOKUMARU Yoshitaka)

From Nakama:

Akihiko is the young master of an unprofitable Kimono shop. He has a sexual relationship with his friend Inoue, the son of a president of a bank, in order to get loans to keep the shop afloat. One day though, his servant, Awata, who has harbored a secret crush on Akihiko, stumbles upon their love affair. After confronting Akihiko to stop selling his body to Inoue for money, Akihiko tells Awata to buy him instead. Awata flees the shop and the house in shame. Several years go by and Awata comes back with untold amounts of money that he has earned in the shadowy underworld of crime in order to buy Akihiko. Akihiko is forced to accept Awata with pleasure and indiginity warring within him.