From SmashWiki, the Super Smash Bros. wiki
Umebura SP was a national Super Smash Bros. Ultimate tournament held in Japan on December 16th, 2018. This is the first Ultimate tournament for the Umebura tournament series, the first Ultimate major in Japan, and, at the time, the largest Ultimate tournament ever. Due to the amount of entrants and time constraints, this became a single elimination tournament.
Super Smash Bros. Ultimate singles