Do you know what ARISF member should be? ARISF - 29 members - International sport federations recognized by IOC - International Olympic Committee. http://www.arisf.org/members.php
And one of these sports is also sport from Japan called SUMO. I don't know how many Sumo fighters or practitioners you know in your country, but it is an interesting decision of IOC. We support fighting sports but on the other hand - popularity and number of competitors should play more important role in recognition of IOC recognized sports (like karate who deserves more than it gets at this moment in international sport evaluation process).
And here is a video from the World champiosnships SUMO - Bulgaria vs. Czech: