[Update: closed]
The scrapbook introducing Nyantsume's twenty resident cats is unusually detailed - not only do you learn each cat's breed and birthday, but English-language descriptions like "innocent cat" and "narcissist cat" give you some insight into their personalities as well. We certainly encountered quite a few lively mousers during a weekday morning visit, with lots of running, chasing and play-fighting among the crew.
The playroom is a big L-shaped living room, and cover charge includes a soft drink (beer and cocktails run a bit extra) plus a complimentary container of kitty treats. We've noticed that this policy of cat snacks for all visitors seems to increase the general alertness of the cat population, but further studies are needed.
The residents here are a diverse mix of attractive breeds, including Selkirk Rex, Scottish Fold, Maine Coon cat, Munchkin and Ragdoll. Two rather outgoing Bengals seemed to be among the ringleaders out on the floor.
Nyantsume (the name roughly means "cat claws" or "claw marks") is up two flights of stairs in an office building, conveniently located near the eastern end of the main shopping and restaurant street of Dotonbori. The cafe is notable for its early opening hours, from 10am.