No Doubt Lilac

Ataru is clumsy, carefree and full of good will. Kyousuke is intelligent, discreet and always ready to help. In spite of their differences, they are like fingers of the hand. Until the day when Kyousuke realizes that he loves Ataru, has the impression to betray their friendship, and decides to bury his feelings. This first unspoken word, between them, is the beginning of a long tear which seems impossible to repair.

(Source: Takeshobo, translated)

Note: Chapter count includes four extra chapters.