Half a century ago, the Tokyo Olympics ushered in a golden age for Japan's capital, as industrial prowess made it the largest urban complex in history. Now the games are returning to mark the end of that growth.

"This will be the final festival," says Yasunari Ueno, 52, Tokyo-based chief market economist at Mizuho Securities Co.

In Tokyo's Shinjuku district, the ground has been cleared for a new national stadium, surrounded by a gymnasium, swimming pools, tennis courts and a baseball arena. Elsewhere, transport systems are being upgraded and new roads, apartments and hotels are being built. The whole infrastructure upgrade could cost ¥2.7 trillion ($22 billion) and together with the games create more than 200,000 jobs, according to Mizuho Research Institute Ltd.