Okinawa houses about two-thirds of the more than 50,000 US troops stationed in Japan under a bilateral security treaty. The arrangement has long been protested by some as an unfair burden on Okinawa, which makes up less than 1 percent of Japan's land space.

Japan remains highly dependent on the US for defense, but crimes by members of the military, including hit-and-runs as well as rapes, have outraged the people of Okinawa. They are also angry about noise pollution and the dangers of crashes from military aircraft.

Still, over the decades the livelihood of many people has become linked to the American troops.

Tamaki, whose mother is Japanese and whose father is a US Marine he has never met, has often said he is a symbol of the predicament of his people.

"I can clearly state we no longer want in Okinawa the US bases that destroy our peace and destroy our nature," Tamaki, 58, said during his campaign.

He has promised policies that care about "the weak," helping workers, students and those who face discrimination.

Before running for governor, Sakima, 54, was mayor of Ginowan, where the Marines air base called Futenma is located.

Futenma is at the center of the controversy over the government relocation plan for US troops to less densely populated Henoko in Nago, Okinawa.

The planning dates back to the 1995 rape of a schoolgirl, in which three US servicemen were convicted. But the planning and construction of Henoko has repeatedly been delayed because of local opposition to the bases.

Some are also pointing to the threat that base construction, which includes a landfill, may bring to the environment, including to a coral reef and dugong and other marine life. 

Sakima, who is backed by Prime Minister Shinzo Abe's ruling Liberal Democratic Party, said he would work with the national government to minimize the US military presence, especially in closing Futenma.

"I will work to move forward on dealing with the reduction of the US troops that we have wanted so long," he said. "If I become governor, I will do my utmost so we can gain the understanding of the people about the Henoko problem."

Both candidates are promising to revive Okinawa, taking advantage of its cultural resources and rich potential as a resort destination.

Outside of Okinawa, the national government as well as public opinion appears to support strengthening Japan's security measures as it faces nuclear threats from North Korea and the growing military might of China. US President Donald Trump's administration also has been pushing Japan to do more to defend itself. (AP)