Also known as: 避尘, 避塵
Bichen is a sword in Grandmaster Of Demonic Cultivation used by Lan Wangji.
It's a Jian (Weapon) with a blue sheath and Sword Tassel. When not in use, it is usually carried on his back.
During a dream influenced by the Mo Incense Burner, Wei Wuxian uses the hilt of Bichen as a Sex Toy to tease Lan Wangji.