Why are these men not wearing shirts? Maybe it's hot, but they're actually in uniform. This is a classroom at a school for sumo, a traditional Japanese sport. Brian Ashcraft of Kotaku has a roundup of more photos and a description of student life there. The Sumo Training School in Tokyo has a 6-month curriculum that includes 2 hours a day inside a classroom. There, the students learn etiquette, calligraphy, and singing, among other subjects.