Kaze Hikaru Vol. 15 (manga)

Doctor Kondo, a respected expert in western medicine, visits the troop. As an act of kindness, the doctor offers to give physical exams to the entire troop, and the men are ordered to strip down to their loincloths. Now Sei seems to be caught in a trap she can't get out of. She's managed to fool everyone else into thinking that she's a boy, but how can she possibly fool a doctor?