Reflecting the recent rise in alpine accidents amid Japan's trekking boom, experts say hikers should get insurance covering search and rescue expenses, which can be extremely expensive.

There were 2,495 mountaineering accidents across Japan in 2016, the second-highest figure since officials began compiling comparable statistics in 1961, according to the National Police Agency. A total of 319 people died or were never found, while 1,133 were injured.

If police or other public organizations are mobilized to deal with a mountaineering accident, taxpayers get the bill for search and rescue operations. But if private rescue teams are called in, the victim must pay the additional costs, which run very high.