 In addition to Japan, it has recently been frequently defended in various independent companies in the United States.The title was created at a time when the company was known as Pro Wrestling Zero-One, originally naming it the Zero-One United States Heavyweight Championship; on July 4, 2004, following Zero-One joining the National Wrestling Alliance (NWA), the title was renamed the NWA/Zero-One United States Heavyweight Championship.On October 26, 2004, Zero-One left the NWA, removing its initials from the title and renaming it the Zero-One United States Openweight Championship.