Rakuten, a Japanese electronic commerce company, has become the bid's 21st official partner.

Tokyo 2020 said the company would "collaborate closely" with the Bid Committee to "help bring Olympism to the heart of Tokyo".

The Japanese bid, which took the opportunity afforded by today's announcement to reiterate its projection that a Tokyo Games would generate more than $950 million of domestic sponsorship revenue, will be hoping that it reminds IOC members of the country's credentials as an international economic powerhouse as they assess the relative merits of the three contenders - Tokyo, Istanbul and Madrid - ahead of the vote in Buenos Aires on September 7.

"Tokyo 2020 offers certainty in times of uncertainty," said Masato Mizuno, Tokyo 2020's chief executive.

"Rakuten's enlistment as official bid partner underscores the Japanese business community's strong desire to contribute its know-how, technologies and creativity towards a dynamic Tokyo 2020."

Hiroshi Mikitani, the chief executive who founded Rakuten in 1997, said its corporate philosophy had "always been to empower people and society through the internet" and that it had "actively engaged in empowerment through sport".

Rakuten, he said, was "fully behind Tokyo 2020's efforts to land the greatest celebration of sport, the Olympic and Paralympic Games".