It is the fourth of the Fuji Five Lakes in terms of surface area, and second deepest, with a maximum water depth of . Its surface elevation of is the same as for Lake Motosu and Lake Shōji, confirming that these three lakes were originally a single lake, which was divided by an enormous lava flow from Mount Fuji during an eruption from 864 to 868 AD. The remnants of the lava flow are now under the Aokigahara Jukai Forest, and there is evidence to indicate that these three lakes remain connected by underground waterways.