After a night of celebrations in Osaka following Friday's announcement in Paris that it had won the 2025 World Expo, Japanese leaders promised an event that would surprise the world, demonstrate that there is more to Japan than just Tokyo, and serve as an international laboratory for co-creation.

But as Osaka woke up Saturday to the news that it will again host the world 55 years after the 1970 Expo, one of the most successful ever with 64 million visitors, there were questions about costs and how winning the rights to hold it might affect another dream of local leaders: to host one of Japan's first integrated casino resorts, and at the same location as the expo.

The decision by the Paris-based Bureau International des Expositions means the city, prefecture, Kansai region, and the central government have less than 6½ years to prepare for the event, which will be held on Yumeshima, a man-made island in Osaka Bay.