This is a bog that is located at the west side of the Yumihari mountains and is called as "Mini Oze in the Tokai region. " A legend says the gray horse of Yoritomo Minamoto was buried here. This is a part of Toyohashi Nature Trail and is the best site for walking in nature. Many rare plants and plants peculiar to the Mikawa region grow there. Shiratamahoshikusa, a kind of pipewort that has pure white cute flowers, Mikawabaikeiso, a kind of false hellebore and Mikawashinjugaya, a kind of nut-rush that are named after this region bloom in each of four seasons. A lot of insectivorous plants also grow in the bog due to its acid soil. A variety of insects including butterflies, amphibians, birds, mammals and land snails that are rare in Japan are found in this bog. Observation tours for the public are conducted in spring and autumn. Research by specialists is carried out in summer and winter. The bog was designated as a natural monument of Aichi Prefecture in 1992.

PlaceIwasaki-cho, Toyohashi City