The Monsters Beneath Mount Fuji: Cryptids of Japan’s Sacred Mountain

Growing up, one of the first images I ever saw of Japan was of it being torn apart by Godzilla. It was late-night television, and that unmistakable roar echoing through the speakers. Buildings crumbled, tanks fired helplessly, and crowds scattered as something massive — something impossible — stomped its way through the city. It wasn’t real, of course. But for a child watching from a world away, it planted an idea: What if something like that could happen? What if there really were creatures hidden in the dark, just waiting to rise?

After spending a few days exploring the mysteries of urban Japan, I decided to leave the neon lights and crowded streets behind and head west. My destination: Mount Fuji. Japan’s most iconic natural landmark, and, as I would soon learn, the setting for more than just postcard-perfect views. Beneath the beauty and serenity, Fuji is home to its own set of legends — stories of giants, lake monsters, and beasts said to walk in the shadow of the mountain. The first story I came across was one I hadn’t expected: Japan’s very own lake monster.

Lake Motosu, one of the Fuji Five Lakes, is a deep and still body of water that rests at the foot of the mountain. In the 1970s, rumours began to circulate of a strange creature living beneath its surface. Locals gave it a name: Mossie, a nod to Scotland’s Nessie. Witnesses described Mossie as being up to 30 meters (98 feet) long, with a body shaped like a crocodile and large humps that rose from the water as it swam. Some claimed to have seen it basking near the shore in the early morning mist, while others said it vanished into the lake before anyone could get close.

Unlike many lake monster legends, Mossie’s story didn’t emerge from ancient folklore, but from modern sightings. Theories about its identity range from a particularly large species of sturgeon to an unknown animal adapted to the depths of the lake. And while there’s no photographic evidence that proves Mossie exists, its story persists, drawing curiosity seekers and cryptid hunters alike.

In the 1980s, sightings continued, and the creature was even allegedly caught on film in October 1987. A Mr. Yoneyama was out with three others taking pictures of the lake and its surroundings when they saw a surge of water out on the otherwise calm lake. Within this surge, they reported seeing 3 to 5 meters of the exposed back of something they could not identify, which was described as being rough like that of a crocodile. They were able to capture the animal on film, but the results proved to be inconclusive.

But while Mossie hides below the surface, another creature tied to Mount Fuji is said to tower above it. The legend of Daidarabotchi goes back centuries and tells of a colossal yōkai — a supernatural giant so massive that its movements shaped the very land. According to one of the most well-known stories, Daidarabotchi once decided to compare the size of Mount Fuji and nearby Mount Tsukuba. He lifted both in his massive hands to weigh them, accidentally splitting the peak of Tsukuba in the process. Satisfied that Fuji was taller, he returned them to their place. The tale is one of strength, scale, and a reminder that in Japanese folklore, the natural and supernatural often share the same stage.

Daidarabotchi is often described as a humanoid giant, large enough to leave lakes in his footprints and valleys in his wake. In some regional versions of the myth, he appears during times of great change or upheaval — as if the land itself is restless. While he’s not considered malevolent, the idea of something so immense roaming the mountainscape adds a layer of awe and unease to the Fuji region.

What fascinates me most about these stories isn’t whether they can be proven. It’s the fact that they exist at all — that people, whether in ancient times or the 1970s, felt compelled to give form to something they couldn’t explain. A ripple in a lake becomes a monster. An earthquake becomes a giant’s footsteps. It speaks to something universal: our need to understand the unknown by imagining it as something living, breathing, and just out of sight. And in the shadow of Mount Fuji, that unknown still feels very present.