As the weekend vote looms by the International Olympic Committee to decide the city that will host the 2020 Summer Olympics and Paralympics, experts in Japan say the three candidates are neck and neck amid lingering worries about the radioactive water leaking from the Fukushima No. 1 nuclear plant.

They feel the outcome will depend on the final presentation and on whether Tokyo can persuade IOC members the city will provide a model for contributing to the future of sports.

The IOC will choose the host city at its general assembly Saturday in Buenos Aires. Some 100 members will vote by secret ballot at the Hilton Buenos Aires hotel, choosing between Tokyo, Istanbul and Madrid. The experts say all three cities have their strengths and weaknesses.