Responses
They already knew each other in Challengers, but volume 2 (page 67) starts a Morinaga dialogue flashback about the time he met Souichi and how they got close.
Also to note, in Challengers, chapters 9-13 (page 49) goes into the time when Morinaga confessed and came out to Souichi, which is mentioned at the beginning of volume 1 of Koisuru Boukun.
Does anyone know what chapter they met for the first time and how Morinaga fall in love with him? Please, let me know. Thanks