Ren'ai Bakumatsu Kareshi ~Toki no Kanata de Hanasaku Koi~

Kyoto, Japan. The heroine meets a man who gives her a pocket watch somehow leading to a Torii in a shrine, and suddenly it warps her into the Bakumatsu period. In the world of where there is such a difference in importance of value, she tries to find a way to go back. When she meets a man who has crossed time and says, "I will live for you," a love story between the two blossoms.

[From MyAnimeList]