A wooden boat carrying the bodies of at least five people washed up on the coast of Sado Island, Niigata Prefecture, suspected of originating from Korea.

Coast Guard official Kei Chinen said the force discovered the bodies and two heads of people on wooden boats this morning and authorities were investigating the cause of the deaths. Mr. Chinen could not confirm whether the two heads belonged to the 5 bodies.

A Coast Guard officer discovered the boat had washed ashore on the Sado coast from yesterday afternoon, but today officials were able to check on the ship due to bad weather. The boat was broken and only the nose. In addition to the hull there are North Korean letters and numbers.

This is the second time a wooden boat has washed ashore on Sado, one of Japan's most remote islands, in the past two months. Due to strained diplomatic relations with North Korea, it is often difficult for Japanese officials to investigate such incidents.

In January 2018, Japanese coast guard also discovered a wreck carrying seven dead bodies on the coast of Kanazawa. In 2017, 104 North Korean ships were washed ashore on the Japanese coast, up from 66 ships in 2016.

According to experts, Korean fishermen are increasingly offshore operations. However, they often use old and poorly equipped ships, which makes it easy to crash. Fishermen also have very few measures to call for help in case of distress.