Tucked away on Japan’s northernmost and wildest island of Hokkaido is a place called Daisetsuzan, a national park known to the Ainu as Kamuimintara, meaning “the playground of the gods.” At approximately 2,267 km sq., it is Japan’s largest national park, and is a place of vast stretches of unspoiled wilderness and a sprawling mountain range often referred to as the “Roof of Hokkaido.” Within this range can be found the mountain called “Asahi-dake,” an active volcano that is Hokkaido’s tallest peak, and which is a mecca for hikers and campers from all over the country, full of scenic vistas and plenty of flora and fauna, yet it is also the location of one of Japan’s stranger unsolved mysteries.
In July of 1989, two hikers and mountaineers from Tokyo headed out on one of the many trails of Asahi-dake. When they did not return as scheduled, concerned friends and family notified authorities, who launched a massive search of the mountain, utilizing ground search teams and helicopters. It was one of these aircraft that would come across a massive “SOS” signal on the ground below near the Chubetsugawa river, fashioned from large birch logs stacked up on top of each other. Seeing this as a promising sign, the helicopter circled the area scouring the wilderness below and they were able to spot the two missing men hiding in a cave about 2-3km north of the sign, who were unconscious but alive and in reasonably good health. When they were revived, they explained that they had been caught in a flash flood and been forced to take refuge in the cave. Authorities commended them on their nice work constructing the prominent SOS sign, crediting it with helping them to find them, but the only problem was, both hikers insisted they had never made such a sign, and that they had never even known it was there at all.
The following day, law enforcement authorities returned to the area to take a closer look at the mysterious SOS sign, thinking that it may have been put up by someone else in distress, and they would turn up some weird clues. They noticed that the construction of the sign had been a fairly ambitious undertaking, with heavy birch logs meticulously stacked three high and up to 5 meters high at the highest point, the whole of it measuring 18 meters long and 5 meters wide, indicating that it had taken some good amount of effort to fashion. Even weirder than this was the discovery of a skeletal dead body nearby, with bones that were broken on places and marked by the gnaw marks from various animals. There was also found a backpack, within which there was found a towel, soap, and a comic book, as well as a Walkman with a tape inside, which contained a chilling message. When the tape was played back, a male voice could be heard to say in a very eerie and disjointed fashion:
I can't move from atop this cliff. SOS. Please help. I am near where the helicopter was originally, and I can't move further due to bamboo brush being in the way. S-O-S. Help me. I'm on a cliff and can't move. Hoist me up! Please get me out of here.
It was very odd in that the man had recorded this message into a tape on his Walkman. Why? There was no way to transmit it anywhere else, so why would he even bother? Also, if he was in such dire shape, then how had he managed to laboriously haul and stack all of those heavy logs to make the SOS sign? Another odd clue was that there was no tool at all found with which those logs could have been cut the way they were. Who was this guy, how had he made that sign, and why had he left this cryptic message on the tape? No one had a clue. Police would eventually identify him as a as Kyoto Institute of Technology graduate and train fanatic, Iwamura Kenji, who had gone missing into the wilds on July 11th, 1984 at the age of 25, leaving all of his belongings and his camera behind at a nearby hostel. He had been lost out in the wilderness for years before that SOS signal and the unrelated disappearance of those other two hikers, so what was going on here?
We are left to wonder just how these two hikers were found so near to this SOS signal they had never heard of before. On top of that, who was the dead guy found near it and how could he have built such a construction in a less than ideal state, and why did he make that odd message on a tape on his Walkman and what was the helicopter he mentioned? Just what exactly is going on here? It all serves to be one on Japan's weirder wilderness mysteries, and there have been no firm answers as of yet.