Lake Ashi (or 'Ashinoko' in Japanese) is a body of water found in the caldera of Mt. Hakone in the southern central part of the Honshu region in Japan. The lake was formed approximately 3000 years ago, after a volcanic eruption altered the landscape and naturally blocked the flow of the Haya river.
Ashinoko is the centerpiece of the Fuji-Hakone-Izu National Park, and is a popular destination for hikers and tourists coming from the nearby resort town of Hakone.
Ashinoko, and the trails surrounding it are reputed to offer some of the most breathtaking views of Fujisan in all of Japan. Unfortunately, cloud cover obscures this view for most of the year. One statistic states that the summit of Mt. Fuji is only visible for 16% of the year, and even on days of visibility passing clouds can obscure the view for long stretches of time.
Regardless of the view of Mt. Fuji, the Fuji-Hakone-Izu park, Lake Ashi, Mt. Hakone and the town of Hakone are all very beautiful and picturesque in their own rights.
The lake has three cruise ships, modeled after pirate ships, that will carry you from Togendai to Moto-Hakone. This is a gorgeous 40 minute trip through misty mountain valleys which seems more like a dream sequence than a lake tour.