Cielerella's manga / #Shounen Ai(57)

Ch 1- 2 a chocolate box where the main character and a guy in the past exchanged letters Ch 2-3 (my favorite) a delinquent looking boy and a cute smol boy. The smol is clueless and the tol boy just wants to be cool and loves smol boy. Ch 5 age gap of 10 years where the child wants to marry the other in the future