The bulwark ruin of Nishijin & Momochi area was originally the center of 20 kilometers of bulwark. In 1274 at the time of Bun-ei invasion, Mongolian army landed in Momochi area. The surrounding areas including Sohara, Torikai and Akasaka were turned into battlefields. The bulwark was built after the battle. Dry stones appeared from under the earth when the ruin was uncovered in 1920. A full-scale investigation was carried out in 1969. It is designated as a national historic site.