Japanese men wear bathrobes without underwear = =

Generally speaking, Japanese men wear bathrobes and underwear.

Bathrobe is a traditional Japanese summer dress, usually made of cotton or other light fabrics, similar in shape to kimono, but compared with kimono, bathrobe is simpler and lighter, suitable for summer wear.

In Japanese culture, bathrobes are generally regarded as traditional summer clothes and are usually used to attend some formal occasions, such as celebrations, weddings and adult ceremonies. Because the bathrobe is light and thin, it needs to be worn with underwear to protect the skin and maintain the comfort of wearing.

So generally speaking, Japanese men wear underwear when they wear bathrobes.