The Sanbagawa Belt is formed of low-temperature and highpressure metamorphic rocks. Isozaki et al. (2010b) divided the Sanbagawa Belt into two sub-belts, based on the ages of the protolith and metamorphism. The protolith of the older sub-belt was the earliest Cretaceous accretionary complex of the Chichibu Belt, and it was subjected to low-temperature and high-pressure type metamorphism of the greenschist to eclogite facies during mid-Cretaceous time (Aoki et al., 2008). On the other hand, the protolith of the metamorphic rocks of the younger sub-belt was the mid-Cretaceous accretionary complex of the Shimanto Belt. This belt was subjected to low-temperature and high-pressure metamorphism of the greenschist to the eclogite facies during Late Cretaceous time (60–70 Ma). The metamorphic rocks of the Kamuikotan and Tokoro belts of Hokkaido can be regarded as contemporaneous with the Sanbagawa Belt. The Abukuma Belt of Northeast Japan is the equivalent of this belt.