Hayato Great Falls, Dual-tiered waterfall in Tanzawa-Oyama Quasi-National Park, Japan

Hayato Great Falls features two successive cascades that drop a combined 50 meters, with a substantial rock formation separating the upper section. The water plunges roughly 40 meters first, then a second drop of around 10 meters continues into the pool below.

The waterfall is listed in Japan's Top 100 Waterfalls, a selection published by the Japanese Ministry of the Environment in 1990. The sources give no ranking number within that list. Its inclusion made the name widely known, even though the falls are rarely visited because of the difficult approach.

The name Hayato-Ōtaki combines the Hayato River with ōtaki, "great waterfall"; the falls are also called the phantom waterfall because so few people reach them. The route follows the Hayato River from the site of the Tanzawa Kankō Center near Honma Bridge, past the abandoned forestry hut and the open ground called Dendō, then along the riverbed to the turnoff into Ōtaki Valley.

Reaching the falls requires approximately two hours of hiking on mountain trails from the nearest road, so sturdy footwear and long clothing to protect against the elements are essential. The path can become slippery in wet conditions, so extra caution is needed.

The falls drop in two plunges, 40 m above and 10 m below, split by a large rock jutting from the middle of the upper fall. The whole cascade can be seen clearly only from the bottom, and the trail there crosses the lip of a small waterfall just before the viewing terrace.