This season will feature 14 Wallabies, including Korobeite, who will be looking to sharpen their skills ahead of the Rugby World Cup in September.
The Wild Knights are yet again one of the favourites to take out the competition after Koroibete starred in an 18-12 grand final win over Suntory Sungoliath to secure back-to-back league titles.
They will be counting on try-scoring weapon Dylan Riley to back up his exploits of last season.
The Australian-born Japan international top-scored for the league with 11 tries, one ahead of controversial code-hopper Israel Folau.
Despite sparkling for the Shining Arcs last year, Folau will play this season in the second division after his club merged with a rival to form the Urayasu D-Rocks.
Australian flyhalf Bernard Foley's Kubota Spears will hope to improve on their third-place finish but face a stern test first up against runners-up Suntory.
His Wallabies teammate Samu Kerevi won't feature for Suntory in their season opener, ruled out until later in the season with a knee injury he picked up at the Commonwealth Games.
Fellow Wallabies star Quade Cooper will likewise miss the first half of the season for Hanazono Kintetsu with an injured Achilles.
The league's chairman, Genichi Tamatsuka, is confident the competition has overcome the setback of its COVID-affected inauguration.
"While the victory and the first title were deservedly won by the Saitama Panasonic Wild Knights, we were all victorious, by getting our new league up and running in such unique and difficult circumstances," Tamatsuka said.
"We appreciate that the number of big-name players and coaches in Japan Rugby League One generates interest for fans far beyond our shores.
"This is something that we are proud of and want to build on as we look to grow."
