The Kintaikyo Bridge in Iwakuni, Japan, is a national treasure with a unique five-span arch structure. To ensure its preservation for future generations, the city decided to pass down the bridge building technology used to construct it. This approach is a first in bridge history. The central three spans of the bridge are proven to be unique arch structures, showcasing the ingenuity of our ancestors. The sustainable technology of the Kintaikyo Bridge is discussed in detail, highlighting the innovative methods used to maintain this historical landmark.