Boku to Watashi no 10-nen Koi

A fifth grader named Tooru has long been in love with Nagisa, a high school student who lives next door. Despite his feelings, Nagisa views him as a younger brother. The story follows their relationship over a decade, highlighting the challenges of a five-year age difference. Originally published in an online magazine with 54 chapters, it was later compiled into 12 larger volumes plus 11 additional chapters.