Discovered during an excavation as part of the Heisei era refurbishing of Sayama Pond, "Osaka's Sayama Pond excavated wooden rainwater gutter / Sayama Pond monument refurbished by Chogen" were designated as significant cultural assets of Japan on August 21st, 2014.
"Osaka's Sayama Pond excavated wooden rainwater gutter" was built during the Asuka period, at the time of Sayama Pond's own construction. It has been preserved along with water collecting parts that include the lower East pipe that was added in the Nara period, and the upper East, Central and West pipes from the time of refurbishment in Keicho, the beginning of the Edo period.
"Sayama Pond monument refurbished by Chogen" is inscribed with details of Sayama Pond's refurbishment that was begun at the beginning of the Kamakura period by the monk Chogen, who oversaw the rebuilding of Todaiji.
These artifacts indicate 1400 years of the pond's history, and are evaluated as cultural assets of great academic worth from which the advanced construction technology from ancient Japan can be confirmed.
Further, the majority of the materials evaluated in this manner are on display in the Osaka Prefectural Sayamaike Museum.