Atsumori-kun no Oyomesan (←Mitei)

Nishiki, who lives out in the countryside, loves studying. But due to the arranged marriage her parents have planned for her, she's finding her hometown a bit cramped. One day, she happens to meet Atsumori, a high schooler from Tokyo. Motivated by his unique sense of values, Atsumori suggests that Nishiki run away with him and get married! Having grown fond of Atsumori, Nishiki decides to chase after him by getting into a high school in Tokyo...?!

(Source: Kodansha Comics USA)