Martial arts schools that teach styles ending with chi or fu far outnumber those that specialize in ones ending with do in Houston. Chalk it up to large Chinese and Vietnamese populations and the better commercial viability of their flashier fighting techniques (the Jackie Chan factor). Those looking to study the Land of the Rising Sun's most sublime style of self-defense can end their search at Diamondback Judo Club. The school has three godans (fifth-degree black belts, for all you mudanshas) on staff and regularly hosts top visiting instructors. (A several-time Iranian champion was once a Diamondback instructor.) Classes are held in a converted industrial garage where there's plenty of room to swoosh your opponent through the air with a hikikomi gaeshi. And there's a thickly padded mat across the floor in case you're on the receiving end.