Wei Collection, Upper Volume
Radical: Bamboo (zhú)
Tuan
Kangxi strokes: 17
Page 896, Entry 22
Broad Rhymes (Guangyun): Pronounced tuan. Collected Rhymes (Jiyun), Rhyme Meetings (Yunhui), and Orthodox Rhymes (Zhengyun): Pronounced tuan.
Explanation of Graphs (Shuowen): A round bamboo vessel.
Also, Broad Rhymes (Guangyun): Pronounced zhuan. Collected Rhymes (Jiyun), Rhyme Meetings (Yunhui), and Orthodox Rhymes (Zhengyun): Pronounced zhuan. People of Chu call the act of breaking bamboo for divination tuan.
Qu Yuan, Encountering Sorrow (Lisao): Seeking the precious grass with bamboo slips for divination.
Commentary: The precious grass is a spirit plant. The slips are bamboo tallies. The people of Chu tie grass and break bamboo for divination, which is called tuan. It originates from bamboo tallies used for divination, so the act of divination itself came to be called tuan, much like how people today use tallies to calculate and count. The same applies.