With the vote to determine the host of the 2020 Summer Olympic Games less than one year away, Tokyo's chances of landing the global extravaganza could slip away in the wake of Japan's ongoing involvement in island disputes with South Korea, China, Russia and Taiwan.

Tokyo is vying with Istanbul and Madrid to host the Olympics, and the winner may well be determined by just a handful of votes.

A historical examination of voting by the International Olympic Committee on the awarding of the games shows that in many instances the host city was determined by five votes or fewer.