Samurai High School (manga)

This is manga. I liked it a lot while reading it, but unfortunately it was kept short.

Promotion

In a modern country where the government is controlled by the Military Force and the samurai are highly respected, the Sakakido family's twins live. Kou, brother, very feminine, very talented in cooking, cleaning, arts and crafts. Tsukiko, the sister, is a masculine, combat-loving martial genius. The twins learn about "Samurai High", where men test their strength and women test their femininity, but the only way they can get there is to switch places. If they are found to be cheating, they will be exiled, so they must overcome their gender differences to keep their secret.