The Koshu Kaido is one of Japan's five great routes from the Edo period, a historic road that stretches approximately 220 kilometers (about 137 miles) from Nihombashi in Edo (modern-day Tokyo) to Kofu, before continuing on to join the Nakasendo route at Shimosuwa in present-day Nagano. Today, this ancient road also feels like a living corridor through Japanese history. Connecting mountain passes, post towns, and landscapes that once inspired ukiyo-e masters such as Katsushika Hokusai, it remains an inspiring path rich in cultural landmarks and memorable sights.
Originally developed in the early Edo period as a military route linking Edo Castle with Kofu Castle, the Koshu Kaido served strategic and defensive purposes. Historical records suggest it may have even been envisioned as an emergency evacuation route for the shogun. By the mid-Edo period, however, the road had evolved into a vital commercial artery, transporting silk textiles and agricultural products from Kai Province (modern-day Yamanashi) to Edo. Religious pilgrims heading to Mount Fuji and Mount Minobu added to the flow of travelers, and along the way, 45 post towns developed to support them with lodging, meals, and other services. Much of the original road follows what is now National Route 20, but traces of its storied past are remarkably well-preserved.