Don't listen to their nonsense It's called a robe. The armor is very thick, and in order to prevent iron pieces from grinding directly on the meat, the samurai will also put on a shirt under the armor. So it will be very hot in summer. For example, when the Jin people escorted Song Gaozong's mother back to the Southern Song Dynasty, because it was too hot, they walked to Beijing and refused to go again. Therefore, when fighting in summer, samurai will wear smocks outside their armor to prevent direct sunlight from burning the armor. This kind of smock has existed throughout the ages, but its style is different. What you said is a little more than that of the Ming Dynasty.