Experts who have studied the 58-day Hainan liberation campaign said the endeavor was a marvel of amphibious operations during the war, with PLA soldiers in small wooden sailboats defeating more than 100,000 Kuomintang troops.

At 35,000 square kilometers, Hainan is China's second-largest island, slightly smaller than Taiwan. It has played an important strategic role as a gateway to the South China Sea.

In late 1949, about 100,000-strong infantry force of engineers, signalmen and anti-tank and anti-aircraft artillery men from the 40th and 43rd Army with the 15th Corps under the Fourth Field Army were dispatched by the central government to the Leizhou Peninsula to form a cross-sea combat corps to liberate Hainan, which was then controlled by Chiang Kai-shek's Kuomintang troops. Some of those had recently retreated in defeat from the mainland, according to the Hainan Chronicles Museum.

The preparation work proved to be extraordinarily difficult, as the cross-sea troops had too few ships and soldiers, though courageous and brave enough in the field, became anxious as they had no experience with the sea. Many were seeing a sea for the first time in their lives, said experts on Hainan liberation history.

They said that over about three months the troops learned how to swim, mastered basic navigation techniques such as boat paddling and steering, determining the wind direction and playing on swings to overcome seasickness. The intensive training mostly took place at night and turned the land force into a navy.