Namaiki Asahi-chan wo Wakarasetai

Ryou is in his last year of high school, and he's enjoying his otaku life to the fullest — except for a certain girl who's really getting on his nerves. She goes to his school and she's none other than his cocky two-year younger childhood-friend, Asahi-chan! Though she's suppose to be his kouhai, she's always teasing him whenever she gets the chance! On the other hand, if she gets teased back, she starts acting like "you can't say anything mean to me because I'm a cute girl." Furthermore, she's "afraid of people with practically no friends who can't be honest with their feelings." Someday, somehow, someone has to set this cocky Asahi-chan straight!

(Source: Kodansha, translated)