Former Taiwan President Lee Teng-hui embarked on a four-day trip to Japan's southernmost prefecture of Okinawa on Friday to pay tribute to Taiwanese killed in the 1945 battle on the island.

Lee's office said the former president, who is visiting at the invitation of the Japan-Taiwan Peace Foundation, is scheduled to meet members of the Friends of Lee Teng-hui Association in Japan on Saturday.

Saturday marks Okinawa Memorial Day, a holiday observed on the island every June 23 to remember the lives lost in the Battle of Okinawa. Taiwan was under Japanese colonial rule for a half century until 1945.

As Japanese Prime Minister Shinzo Abe is also slated to attend a memorial service at the same park on Saturday, attention is focused on whether the two old acquaintance will make contact.

On Sunday, Lee, 95, will visit Peace Memorial Park, located in the Mabuni Hill area of Itoman city, to attend a plaque-unveiling ceremony for a monument honoring the Taiwanese who died in the bloody battle.

Mabuni Hill was the final command post of the Japanese army in Okinawa and the place where the 1945 battle came to a bitter end. More than 200,000 people, both civilian and soldiers, died in the latter days of the Pacific War.

(Lee Teng-hui at Naha Airport in Okinawa)

During his stay on the island, Lee, accompanied by his wife Tseng Wen-hui, will also meet with Taiwanese expatriates and Taiwan's de facto ambassador to Japan Frank Hsieh. He is scheduled to head back to Taiwan on Monday.

Taiwan's first popularly elected leader, Lee is on his ninth visit to Japan since stepping down from the presidency in 2000. His last visit was in July 2016, when he traveled to the southern island of Ishigaki.

Growing up under Japanese rule in Taiwan, Lee developed an affinity for Japan even before he went to study at Kyoto Imperial University, now known as Kyoto University, during World War II.

When he was in power in 1999, Lee infuriated China by defining ties across the Taiwan Strait as a "special state-to-state relationship."

China has criticized Japan for granting Lee travel visas, labeling him a "separatist" and accusing Tokyo of providing him with a political platform to advocate Taiwan independence.

Taiwan has been governed separately from the mainland since they split amid a civil war in 1949. Ever since, Beijing has considered Taiwan a break-away province awaiting reunification, by force if necessary.