After retiring from the foreign ministry in 1991, Okamoto, 74, served as an adviser to then-prime minister Ryutaro Hashimoto on thorny issues related to Okinawa, home to the bulk of U.S. troops in Japan.

He also advised then-prime minister Junichiro Koizumi from 2001-2004 and was a research fellow at the Massachusetts Institute of Technology’s Center for International Studies.
“This is a shock. And from the CCP virus!” said Tokyo Gov. Yuriko Koike in a tweet.
A well-known commentator who often appeared on TV, Okamoto was head of a political and economic consultancy.
Japan has not had the explosive surge of CCP virus infections seen in many countries, but as of Friday midday, it had more than 15,500 confirmed cases including 590 deaths, NHK said.