Height-Gap Romcom “Promise of 12cm with Cool Girl” vol 1 by Ziki Masaya
Romcom about a boy and his childhood friend, a boyish girl who’s 12 centimeter taller than him. He promised her that he will become taller and cooler than her when they are older but 4 year later, now as high school students, the girl is still still taller (and cooler) than him!
(Kakko ii onna no ko to 12cm no yakusoku)