The Japanese attempted to play a trump card in the face of a Fukushima crisis threatening to derail their hopes of staging the world's greatest sporting extravaganza.
Tokyo stressed its economic strength and the opportunities available by tapping Asia as it continues to try to woo members of the International Olympic Committee.
Some 100 IOC members will on Saturday choose between Istanbul, Madrid and Tokyo for the host city of the Games.
While Tokyo focused on finances, Istanbul placed athletes at the centre of its bid, promising them an unrivalled experience, and Madrid highlighted its support and backing at home.
Tokyo had been seen as an early favourite, with Madrid hurt by Spain's ongoing economic woes and Istanbul suffering from anti-government protests, the escalating war in neighbouring Syria and a series of doping scandals.
But while Tokyo had been regarded as a financially safe choice, many commentators and people close to the city-selecting process in Buenos Aires are now saying the Spanish bid is gathering pace fast.
The Argentine capital was abuzz with talk of Fukushima after trade and economics minister Toshimitsu Motegi told Reuters that Japan's government is in touch with experts in the United States and elsewhere on ways to control the crisis.
Tokyo's case can hardly have been helped by the news once more placing Fukushima squarely in the spotlight.
But bid leader Tsunekazu Takeda told reporters he had written a letter to IOC members to stress radiation was not a threat to Tokyo, located some 230km (140 miles) from the stricken plant.
"Right now Tokyo's radiation level is comparable to London, Paris and New York and here as well," Takeda said. "It's absolutely safe."
Instead, the Japanese team were hoping to appeal to the IOC's business sense in the high-stakes contest.
It promised to showcase Asia's great potential and highlighted the opportunity offered by choosing a city in the world's largest continent.
Fujio Cho, President of the Japan Sports Association and honorary chairman of Toyota Motor Corp., said the Olympic Movement could only benefit with Tokyo as host.
"Asia is the only continent in the world with more people living within its territory than outside," he said.
"Consequently it is the largest market in the world, with billions of passionate sports fans."
Much talk among commentators has been about the state of the Spanish economy - seen as Madrid's Achilles heel - and Takeda highlighted that Japan had recently reported its lowest rate of unemployment since October 2008.
Japan's July 2013 figure of 3.8 percent - in stark contrast to the Spanish figure of some 26 percent - is an indication of the strength of the country's economy, according to Takeda.
While Tokyo spoke of the economy and benefits of unlocking Asia's potential, Istanbul bid chiefs spoke of their city's history and focused on athletes, promising them an unrivalled experience were the Turks to win the contest.
"Imagine being a marathon runner crossing continents over the Bosphorus Bridge, a triathlete racing alongside Istanbul's 2,500 year-old city walls or a volleyball player spiking for the match with the Bosphorus at your back," Turkish IOC member Ugur Erdener told reporters.
"Istanbul has that magic athletes thrive on and they will be at the centre of the greatest stage in 2020."
Madrid, meanwhile, emphasised the broad popular support it is getting from Spaniards, citing an August poll which showed 91 percent of them now support Madrid's bid, up from around 80 percent earlier in the year.
Their bid was bolstered by the arrival of NBA star Pau Gasol who jetted into Buenos Aires earlier in the day.
The Los Angeles Lakers player, Spain's flag-bearer at the London 2012 Games, said he was proud to be part of such a "fantastic" team.
"We have a very strong bid," he said. "We want to show them that if they choose us, we'll be putting on a great Olympics in 2020."
- Sports & Recreation