The stereotypical image of middle-aged Japanese men may be stiff and proper, but you are bound to think differently when you see those who are passionate about paper sumo matches. The Nihon Kamizumo Kyokai (Japan Paper Sumo Association), boasts a history of more than 60 years, and its members enjoy having sumo matches with wrestlers made of cardboard fighting it out in a ring the size of your palm.

"Wow, he finally halted a losing streak!" exclaims a member during the group's most recent tournament, which was held in September at the Tokyo home of 56-year-old Tadahiro Yoshida, head of Nihon Kamizumo Kyokai.

The participants are huddled around a 12-centimeter ring placed in what they call the Kokugikan, a miniature replica of Ryogoku Kokugikan, Tokyo's sumo hall.