Within sight of the bright lights and bustling beaches of Busan, sleepy Tsushima Island has little in common with its neighbor located a mere 50 kilometers north, but the island of about 31,000 people has recently become a hot spot for South Korean tourists.

Duty-free shops abound in the center, advertising Japanese goods in Korean, and groups of Korean tourists, day-trippers in many cases, are everywhere. The island received 356,316 Korean visitors in 2017, up 37.1 percent from the year before, making international tourism a vital source of revenue.

Tsushima, which also has a long, colorful, and often bloody history with the Korean Peninsula, made headlines for a different reason late last year when it was reported it could become the focal point of a large-scale evacuation should tensions flare between Seoul and Pyongyang.

Despite recent signs that tensions over North Korea’s missile and nuclear weapons programs are easing, the central government is reportedly exploring an evacuation plan that would bring tens of thousands of Japanese in South Korea to Tsushima, in the event of a military incident. Local residents and politicians, however, worry that the island’s infrastructure is ill-equipped to handle a large stream of evacuees.

The plan, reported in media on both sides of the Tsushima Strait late last year, could see nearly 38,000 Japanese nationals living in South Korea, as well as Japanese tourists in the South, evacuated via Tsushima in the event of a military clash with the North. Air, Maritime and Ground Self-Defense Force elements based on Tsushima would take the lead in getting people from Busan to the island before transporting them on to Honshu or Kyushu islands.

As the island has recently become a popular destination for South Koreans via ferries from Busan, there is also concern over what to do about any South Koreans who find themselves evacuated to or stuck on Tsushima.

But on Tsushima itself, there is little information available about what might happen in the event tens of thousands of people arrive, even if their stay is temporary.

“What the evacuation plans would entail, how they would be carried out, and what kinds of advance preparations that would be needed are all things that the local governments in Tsushima and the Nagasaki Prefectural Assembly have yet to hear about,” Tomonori Sakamoto, a Liberal Democratic Party member of the Nagasaki Prefectural Assembly from Tsushima, said in an interview.

Chizuru Yoshinaga, who works at Sakamoto’s Tsushima office, questioned the island’s ability to handle large numbers of evacuees.

“For example, there aren’t a lot of qualified medical personnel on Tsushima … and the number of medical facilities is quite limited,” Yoshinaga said. “Many elderly residents seek treatment in Fukuoka or Nagasaki, but transportation can also be problematic. It’s nearly five hours away by ferry and two and a half hours by hydrofoil to Fukuoka.”

When asked to comment on the issue at a January news conference, Defense Minister Itsunori Onodera offered only vague comments on the possibility of evacuating people to Tsushima, saying the government believes it’s an important location in terms of security and it has been studying various options to protect the lives of Japanese nationals.

Yet for many Tsushima residents and visitors, the most pressing issues related to the island are not military or political but economic. Thanks to a law that went into effect last April, Tsushima is one of 15 island groups eligible for central government funding.

Through the new legislation, “The central government helps subsidize the cost of running the ferries and gives island residents a big discount on flights, although those who are not residents still pay more,” said Kazuaki Ogi, a Fukuoka resident who visits Tsushima regularly on business. “In addition, local fishermen receive different kinds of help that make it easier to get seafood caught in Tsushima waters sent to other parts of Japan.”

According to the city of Tsushima, after the law went into effect there was nearly a 9 percent increase in the number of island residents taking advantage of cheaper fares for the four daily flights to Fukuoka and the four or five daily flights to Nagasaki, both with a flight time of about 30 minutes.

Whether this will lead to more people visiting, and possibly even relocating, to Tsushima has residents wondering.

Like most of Japan, the population of Tsushima is aging and decreasing. About 34 percent of Tsushima residents are over 65 years old, and in 2013, the National Institution of Population and Social Security Research predicted Tsushima’s population will drop to around 18,000 by 2040 from the current 31,000.

Its proximity to South Korea means that islanders need Korean tourists to help the local economy, but residents are also worried wealthy Koreans will buy up property that’s been passed on to heirs who don’t want it.

In 2014, concern was raised locally and by right-wing nationalists after it was learned that South Korean businesses were buying up real estate near the Maritime Self-Defense Force’s Tsushima base.

“There were concerns about the land being used for spying purposes,” Sakamoto said.

Meanwhile, international tourism continues to be a vital sector of the Tsushima economy.

“It’s a very tough situation. Korean tourists help the economy, and some new hotels and restaurants are being built for them. But we also want to effectively encourage younger Japanese to come to Tsushima and perhaps even move here,” said Yoshinaga.

Throughout its long history, Tsushima has been a survivor on the front lines of East Asia. It’s been a quasi-independent fiefdom that survived a Mongol invasion, and a base for bands of wako pirates who raided the coasts of Korea, leading to an attack by Korean rulers. It’s also close to the area in the Tsushima Strait where the Japanese navy defeated the Russians in 1905, ending the Russo-Japanese War.

Today, despite attention in Tokyo over what to do with Tsushima in the event of a new Korean war, local residents are more worried about ensuring that enough of them remain, and prosper, so that the island’s rich culture will continue to flourish.