Around 70,000 people protested the Japanese government’s plan to relocate a US air base within Okinawa island.
Locals say the base will hurt the environment and claim they have sacrificed enough for Japan’s security alliance.
The demonstrators gathered at a park in the prefectural capital of Naha on Saturday, in an attempt to urge the central government to abandon their plan to transfer the US Marine Corps Air Station Futenma from the crowded town of Ginowan to the less populated coastal region of Nago.
Okinawans want to block the government’s plan to start dumping soil into Henoko Bay within days to make a landfill for the new site. Environmental groups say construction at the bay risks corals and dugongs, the endangered marine mammals.
The prefecture is already home to the majority of US military facilities and about half of the 50,000 American troops in Japan.
But the Japanese government think the base is necessary for Japan to maintain the perceived deterrent a US base provides, while citizens on Okinawa see it as an unfair burden.
Participants also held a one-minute silence to pay respect to the late governor of Okinawa, Takeshi Onaga, who died of cancer on Wednesday, in the midst of his aggressive anti-US base campaign against Prime Minister Shinzo Abe’s administration.
Deputy Governor Kiichiro Jahana, who has taken over Onaga’s governmental duties, told the crowd he would be continuing his predecessor’s fight to retract the approval for landfill work for the base relocation, given to the central government by the former governor before Onaga.
Okinawa has been asked to make the sacrifice for the sake of mainland Japan for years.
Okinawa was Japan's only battleground in the final days of World War II, and the island remained under US rule for 20 years longer than the rest of the country.