The 18-year-old saw a switch to the Santiago Bernabeu announced on Friday.
He is already accustomed to gracing the books of a La Liga heavyweight, after Barcelona drafted him into their famed La Masia academy system back in 2011.
After four years, they were forced to let him go after being found guilty of rule breaches regarding the acquisition of U18 players.
Kubo was forced back to his homeland and has enhanced his reputation during a spell with FC Tokyo.
Madrid have now brought him back to Spain and offered him another shot at becoming a superstar in Europe.
Much is expected of Kubo, with a billing as the ‘Japanese Messi’ having followed him around for some time.
That moniker could be considered both a blessing and curse, with added expectation being piled onto a youngster who is still very much in the infancy of his career.
Kubo is aware that he cannot claim to have achieved anything at this point, with the Messi talk something for others to worry about.
He told reporters when quizzed on the comparisons: “It's something to be very proud of and I feel honoured but I'm not at that level yet.
“I want to focus on improving the skills I have now.”
Kubo has joined Real to link up with their Castilla side and will be eased into the fold by the Blancos.
That should help to keep him out of the spotlight and allow him to further his development in relative peace.
“I only need to express the way I play, nothing more,” Kubo said of the challenges he faces.
He is unlikely to be given a senior first-team stage on which to perform by Madrid any time soon, but currently has one at international level.
With his Real switch wrapped up, there will be plenty of eyes on Kubo when he takes to the field with Japan at the 2019 Copa America.