TOKYO -- Japan's capital is set to lay claim to the country's tallest building in 2023, when developer Mori Building aims to complete a 330-meter tower as part of a major redevelopment.

The 64-story main tower of the 580 billion yen ($5.45 billion) project unveiled Thursday -- the company's costliest to date -- would beat out Osaka's 300-meter Abeno Harukas skyscraper. It will contain a mix of office and residential space.

The project represents the developer taking on a "massive challenge," CEO Shingo Tsuji told reporters here Thursday. Ground finally broke on the development this month after 30 years of negotiations with about 300 landowners and other stakeholders.

The roughly 81,000 sq. meter "city within a city" in the Toranomon business district would include a luxury hotel from an overseas brand, as well as an international school that would rank among Tokyo's largest. It is planned to feature a large, nature-filled central plaza for residents and visitors to enjoy. Mori Building anticipates between 25 million and 30 million visitors annually.

Floor area across the complex's three towers will total about 860,000 sq. meters, with over 210,000 sq. meters of office space and about 1,400 residential units, surpassing Tokyo's Roppongi Hills -- another Mori Building development -- on both counts. Commercial and cultural facilities will also figure into the Toranomon project.

The new skyscraper may not retain the top spot for long. Mitsubishi Estate plans to complete around 2027 a roughly 390-meter tower -- slated to be Japan's tallest at that point -- north of Tokyo Station in the Marunouchi district.