Koikuchi-shirt was used as underwear for Kimono at the times of festivals because the material is cotton, and it can absorb sweat and dry quickly. As the pattern has become versatile, it has been used as a main shirt rather than as underwear.
Recently it is worn as a uniform for restaurants which offer Japanese food as well as casual wear for Japanese who like festivals. It is becoming the representative of "Japan taste casual clothes."

Tamura Sho-Ten Original “Fuck Sake” product