The player will represent the club's Castilla side for one season before moving into the first-team in the same manner as Vinicius Jr had agreed upon his transfer in the start of the 2018/19 campaign. The top level of the madridista academy are set to get their hands on one of the most promising youngsters in world football.
Barcelona have kept tabs on the player since, but Real Madrid now look to be the front-runners to sign Kubo, whose dribbling skills made him a YouTube hit as a small boy.More news: Hannity: Trump playing Democrats and the media 'like a flute'
Kubo had previously been at Barcelona's La Masia for four years between 2011 and 2015 but the club had to release the then 14 year old.
He has scored four goals in 13 J-League games this year for Tokyo.
On Thursday, Kubo took part in training with Hajime Moriyasu's squad in San Paulo ahead of the 12-team tournament to be held between Friday and July 7, but left without speaking to reporters.
Turning 18 has meant he can officially move back to Europe.More news: NASA Spots 'Star Trek' Starfleet Logo 'Dune Footprints' on Mars
Los Blancos have already spent big this summer signing Eden Hazard, Luka Jovic, Ferland Mendy and Eder Militao and could yet add more.
Kubo, who has been dubbed the "Japanese Messi", made his full worldwide debut against El Salvador earlier this month and was also linked with Barcelona, Paris Saint-Germain and Premier League champion Manchester City.
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