Japan Coast Guard officials have confirmed that this year there have been 105 incidents in which wooden boats, presumably from the Korean Peninsula, have washed ashore, or have been found drifting in Japanese waters.
The officials say the number of such cases exceeded last year's figure of 104 as of Thursday, making 105 the highest since the recordkeeping began in 2013.
They say 12 people were found dead in 5 cases, and that boats in the remaining 100 cases were empty, while some occupants were discovered alive last year.
In recent years, North Korean fishing boats have been operating in the Sea of Japan, in part to earn foreign currencies. Some boats have repeatedly been fishing illegally in Japan's exclusive economic zone.
Japan's Coast Guard has responded by issuing warnings to the operators of such boats, and spraying them with water.
The Coast Guard is stepping up patrols as the number of suspected North Korean boats found on or near the Japanese coast tends to increase around this time of year.