On this day, 36 years ago, on July 31, 1989 (June 29, 1989, the Tang Dynasty iron ox was unearthed in Yongji County. On July 31, 1989, four Yellow River "Zhenhe Da Tie Ox" forged during the Kaiyuan period of the Tang Dynasty were unearthed on the Yellow River beach outside the west gate of the ancient Puzhou City site, 12 kilometers away from Yongji County City, Shanxi Province.