Yuhuan is a round jade with a hole in the middle, which is similar in shape to a bracelet. Its hole diameter is larger than the edge, and some are equal to the edge. Similar to this instrument are jade bi and jade Ji.

Yuhuan was popular from Neolithic Age to Ming and Qing Dynasties. The basic shape of Yuhuan in Neolithic Age was a flat circular ring, which was mostly made of white jade and topaz. The whole is round and smooth, with straight inner and outer walls, and some rings have small round holes opposite to the drill, and the hole walls are inclined and straight. Yuhuan center is slightly thicker, the edge is thinner, the whole body is polished, and the production is exquisite.

Extended information:

Yuhuan and Yujun are similar in shape, but there is a gap in Yujun. It is precisely because of this gap that these two kinds of round jade express two completely different messages. Yuhuan indicates repair and approval, and Yujun indicates breaking up and opposing.

Three years later, if the criminal exiled to the border in ancient times got the Yuhuan sent by the king, he would know that the king called him back, because the ring was homophonic. If he got the jade Jue, he would know that the king had cut him off and there was no hope of returning, because it was near the sound of Jue. In ancient times, Huan and Jue were also used together. According to the choice of Huan and Jue, we can know whether the person's attitude towards something is approval or opposition.

Baidu Encyclopedia-Yuhuan