She is Kinshiro's wife.

Kei, the daughter of a powerful Hatamoto, is suddenly ordered by her father to marry a man named Kinshiro Toyama, who has abandoned the life of a samurai and is now a gambler. The man she is to marry is a man who has abandoned the life of a samurai and is now a gambler. His name is Kinshiro Toyama! Kei decides to go to Asakusa to appeal herself as a signboard girl at the inn where Kinshiro is staying...?