Mainz 05 brace for major Kaishu Sano battle as RB Leipzig step up interest | OneFootball

RB Leipzig have reportedly emerged as one of the leading candidates to sign Mainz 05 midfielder Kaishu Sano amid growing interest in the Japanese international from across Europe. According to Japanese outlet Sponichi, Leipzig are currently showing particularly strong interest in the 25-year-old and could become serious contenders for his signature.

Liverpool have also recently been linked with Sano, while Sponichi reports that several Bundesliga clubs as well as sides from the Premier League and Serie A have made enquiries. Leipzig – in large part due to Christoph Baumgartner’s recent injury news – are nevertheless described as presently displaying the strongest interest.

Any deal would require a substantial investment. Sano remains under contract with Mainz through 2028 and does not possess a release clause, leaving the Rheinhessen in a strong negotiating position.

Sporting CEO Christian Heidel made Mainz’s stance particularly clear in May, describing Sano as “the heart of our game.”

“You wouldn’t even get one of his legs for €25m,” Heidel said when discussing potential valuations.

The Mainz executive also insisted that any eventual departure would “100 percent” constitute a new club-record sale.

Sano developed into Mainz’s midfield engine

Such a valuation reflects Sano’s extraordinary development since arriving in German football from Kashima Antlers in the summer of 2024. The Japanese midfielder quickly established himself alongside Nadiem Amiri at the heart of Mainz’s midfield and became one of the Bundesliga’s most durable performers.

Get German Football News highlighted Sano’s remarkable availability after his first Bundesliga goal last September. Sano started all 34 league matches during his first Bundesliga season and played the full 90 minutes in all but two. By the time of Mainz’s 4-1 victory over Augsburg in September 2025, he had logged 3,884 of a possible 3,900 competitive minutes during his first year-plus with the club.

That Augsburg match also demonstrated another dimension to his game. The defensive midfielder recorded his first Bundesliga goal and first two assists in the same fixture, while maintaining that his primary responsibility remained working for the team and providing defensive stability.

His market value rose accordingly. Sano had arrived at Mainz for approximately €2.5m and was already valued around €20m by the early stages of his second Bundesliga season.

Transfer interest has continued to grow

It did not take long for other German clubs to take notice. GGFN reported in November that Eintracht Frankfurt had identified Sano as a potential defensive-midfield reinforcement. By that stage, his estimated market value had reached approximately €25m and Mainz were already considering how they might eventually cope without him.

Japanese midfielder Sota Kawasaki arrived during the summer of 2025 and was initially viewed as a potential long-term successor. Mainz were subsequently also linked with Sano’s younger brother Kodai, currently at NEC Nijmegen. Get German Football News covered that possibility in December, noting that Mainz increasingly appeared to regard Kaishu Sano’s eventual departure as inevitable rather than imminent.

GGFN reported during the January transfer window that Mainz were highly unlikely to consider offers for Sano while fighting to preserve their Bundesliga status.

European performances further increase Sano’s profile

One of his strongest performances arrived in April against Racing Strasbourg. Sano won possession in midfield, combined with Kawasaki and finished a superb individual move to open the scoring in Mainz’s 2-0 victory. GGFN named him Player of the Match with a rating of nine.

The performance was particularly notable because Sano remains fundamentally a defensive midfielder rather than a player known for attacking production.

His subsequent World Cup appearances have only increased his international profile and the number of clubs monitoring him. Leipzig now appear prepared to join that race in earnest.

GGFN | Peter Weis