Tokyo Disneyland's Mark Twain riverboat is so large that it is required by law to be registered. Its home port is listed as Urayasu. From the time of its opening until September 2006 its sponsor was Nippon Suisan Kaisha.
Board the Mark Twain Riverboat, an elegant, 3-deck "floating palace," for a cruise around the Rivers of America. It's even more romantic at night when the steamboat is all lit up!