Former Taiwan President Lee Teng-hui will visit Japan in early May and deliver speeches at events in and around Tokyo, sources close to Lee said Wednesday.

Making his first trip to Japan since 2009, the 90-year-old former leader will attend a reunion on May 9 in Zama, Kanagawa Prefecture, for former teenage engineers from Taiwan who worked at an Imperial Japanese Navy factory there during World War II, they said.

However, the trip hinges on the health of Lee, who was hospitalized between late March and early April for flu complications.

Lee, the island’s first directly elected leader, is known for his friendly stance toward Japan, which ruled Taiwan for 50 years through the end of World War II in 1945. The elder statesman has said the disputed Senkaku Islands in the East China Sea belong to Japan.

The Japan-administered islets are also claimed by China and Taiwan and his remarks in Japan could anger Beijing.

The upcoming Japan visit will be his sixth since he stepped down as Taiwan’s president in 2000.

He has traveled to various parts of Japan after his retirement, triggering protests from China, which regards Lee as a “separatist” due to his strident assertion that Taiwan is an independent, sovereign state.

China regards Taiwan as a renegade province that must be brought into the fold.

About 300 former teenage engineers from Taiwan will attend the ceremony, in which former Prime Minister Yoshiro Mori and Takeo Hiranuma, deputy head of the opposition Japan Restoration Party, will also take part.

The sources said the former president agreed to join the event, which will commemorate the 70th anniversary of the arrival of the first group of the Taiwan engineers in Japan, to “further strengthen Taiwan’s relations with Japan.”