Vasuki (Sanskrit: वासुकी, वासव) is a Sanskrit name for a naga, one of the serpents of Buddhist and Hindu mythology. He is a great King of the nagas and has a gem (Nagamani) on his head. Manasa, another naga, is his sister. Vasuki is known in Chinese and Japanese mythology as being one of the "eight Great Naga Kings" (八大龍王 Hachi Ryuu-ou), amongst Nanda (Nagaraja), Upananda, Sagara (Shakara), Takshaka, Balavan, Anavatapta and Utpala. Vasuki was also the name of the devout wife of the Tamil poet Thiruvalluvar.