Chou to Hana no Kankeisei
Complete | Akabeko | 2017 released
Nights Before Night
Complete | Kazuki Natsume | 2000 released
A owns a brothel and is forced to look after C, the brother of A's dead lover B. They were/are all part of the yakuza, C is the son of the head, A suffers insomnia from guilt at being the cause of the death of his lover
Itoshii, To Iu Koto