Kaze Hikaru, tome 05
Taeko Watanabe2007

Sei seeks out Saito Hajime to help her master a difficult sword technique, and Saito is confused by his amorous feelings for Sei, not knowing that she is a girl in disguise. As if things weren't complicated enough, it seems a truly male Sei look-alike has taken a fancy to Saito--and plans on seducing him!