Sono Koi Yoki ni Hakarae!

"I like you, please go out with me."

The romantically-challenged history teacher Suzuki-sensei has finally received her first confession of love!? But wait, her suitor Watanuki is just a high school student, and they're both girls, too! So she can't possibly accept the sudden confession? As a student of history, Suzuki-sensei will have to rely on the teachings of the warlord Uesugi Kenshin for advice on how to navigate the battlefield of love!

(Source: Comic Days, translated)