In most parts of North China Plain today, there is a legend about Sophora japonica in Hongdong, Shanxi. The content of this legend is: our ancestors moved from under the big locust tree in Shanxi; The locust tree in Hongdong, Shanxi Province is the birthplace of our ancestors and our root. This legend is distributed in today's central and southern Hebei, western Shandong, central and southern Henan and most areas north of Huaihe River in Anhui. In some areas, Sophora japonica has become an old crow's nest-an old crow's nest on Sophora japonica. Sophora japonica is not only passed down from mouth to mouth, but also engraved on ancient tombstones and written on crisp yellow genealogy.