Tower of the Sun Named Important Cultural Property; Icon of Osaka Expo 1970 Symbolizes Japanese Postwar Economic Boom

The Yomiuri Shimbun

13:16 JST, May 17, 2025

The Council for Cultural Affairs on Friday officially recommended to the education, culture, sports, science and technology minister that the Tower of the Sun, a symbol of the 1970 World Exposition designed by artist Taro Okamoto and located in Suita, Osaka Prefecture, be designated an Important Cultural Property in the building category.

With Osaka now hosting another World Expo, 55 years after the one for which the tower was constructed, the structure has been recognized as a valuable legacy representing Japan’s era of rapid economic growth.

Under the leadership of Okamoto, the tower of the Sun was erected as the centerpiece of the Expo’s Theme Pavilion. In response to the Expo’s slogan, “Progress and Harmony for Mankind,” producer Okamoto deliberately conceived the tower as an antimodern symbol reminiscent of an ancient Jomon clay figurine.

The tower left a powerful impression on visitors and became a public favorite. The construction of the tower’s enormous and distinctive form, 70 meters tall, brought together some of the most advanced techniques of the time.

Mathematical analysis was applied to shape the trunk’s complex three-dimensional curves, and the 25-meter-long arms, whose interiors have spaces visitors can enter, were engineered to a strength that would be challenging to achieve even with today’s technology.

Although the tower was slated for demolition once the Expo closed, petition drives and other opposition efforts secured its preservation. After seismic retrofitting, the interior was opened to the public in 2018 for the first time since the Expo.

It will become Japan’s second newest Important Cultural Property in the building category, after the Seto Inland Sea Folk History Museum in Takamatsu, which was completed in 1973.

Prof. Osamu Goto of Kogakuin University, a specialist in Japanese architectural history, said: “Few cultural properties allow so many people to look back on history with a shared awareness. This is an unusual structure with multifaceted value, and it could one day be designated an Important Cultural Property in the fine arts category as well.”