Introduction to the jade articles of the Xia Dynasty: The large-scale jade articles unearthed from the Erlitou site include four colors of jade zhangs, seven-hole jade knives and jade congs, which confirms the "Li of Zhou·Spring Palace·Dazongbo": "Using jade as six utensils, Honor the four directions of heaven and earth, the green Zhang to the east, the white Zhang to the west, the Xuanzhang to the north, and the red Zhang to the south, that is, the green dragon in the east, the white tiger in the west, the red bird in the south, the Xuanwu gods in the north, the gods of the four directions with jade congs and seven Kong Jade Swords to Sacrifice Heaven and Earth. "The heavy weapons used by the emperor to worship heaven are concentrated in this site, which fully proves that the Erlitou site was the center of state power of the Xia Dynasty.