12cm Promise with a Cool Girl

Tomoaki Kamba admired his boyish childhood friend, Ibuki Tachibana, and promised to become "more cool" than her. However, four years have passed, and Ibuki has grown up to be an even more handsome girl! Their relationship is as unchanged as a 12cm height difference that cannot be filled...? The curtain rises on a pure love story about a cool girl who is sorely in love with a boy who wants to be cool! (Source: Ichijinsha, translated)