Read Manga Kakkoii Onnanoko to 12-centi no Yakusoku online in English. Also known as A Cool Girl and a 12cm Promise and 12cm Promise with a Cool Girl.

Tomoaki once promised his boyish childhood friend Ibuki that he'd grow up to be cooler than her. Four years later, high school brings them back together, but Ibuki has become an even more striking and confident young woman, standing twelve centimeters taller.

Their everyday moments together blend the comfort of long-time friendship with subtle new feelings and gentle confusion. As the old promise lingers between them, small interactions hint at something deeper and more tender than either expected.

This series may appeal to readers who enjoy sweet romance, childhood friend stories, and lighthearted slice-of-life tales.