Okubo Pond and Mizubasho
Okubo Pond is located approximately 3 kilometers uphill in the direction of Mt. Haku from the village of Ogimachi, and sits 718 meters above sea level. The pond is thought to have been formed when a landslide blocked a small river that flowed through the valley. Streams from the southern slopes that once fed the river now empty into the pond, which also has a number of underwater springs. The pond is 50 to 130 centimeters deep and is almost entirely covered by marshland, which provides a habitat for various plants and animals rarely seen elsewhere in the Shirakawa area.
The most famous of these species is mizubasho (swamp lantern; Lysichiton camtschatcensis), which grows in large colonies mainly at the pond’s far end and whose white lily-like flowers bloom immediately after the snow melts, usually from late April to early May. The mizubasho of Okubo Pond are designated a Natural Monument of the village of Shirakawa and attract a steady stream of plant enthusiasts every spring.
Other notable plants in the pond include katakuri (Asian fawn lily; Erythronium japonicum), whose purple and pink blooms follow those of the mizubasho, and zazenso (Eastern skunk cabbage; Symplocarpus foetidus), which produces distinctive purple-hued flower sheaths that often emerge while there is still snow on the ground. The shape of these sheaths is said to resemble a Buddhist monk engaged in zazen, or seated meditation, hence the name zazenso (“zazen plant”).
Also native to the pond are creatures like the yellow-and-white-striped Gifu butterfly (Luehdorfia japonica), which can be seen fluttering around the area from May, more than a dozen species of dragonfly, and fish such as carp and iwana (whitespotted char), an East Asian species of trout.