吾妻鏡
From above today's Daibutsu Tunnel, the passed through the localities of Kajiwara and Yamazaki to link Kamakura to Fujisawa. Its date of construction is unknown, and the Azuma Kagami doesn't mention it. A passage of the Shinpen Kamakurashi seems to indicate that by 1181 it existed, but this is probably an error. Repaired many times in the period from the Edo period to the Meiji era, it has been declared a Historic Site.