Chou Collection, Middle Volume Radical: Earth (tǔ) Sao; Kangxi strokes: 11; Page 231, Entry 18 Tang Rhyme (Tangyun), Collected Rhymes (Jiyun), Dictionary of Rhymes (Yunhui), and Orthodox Rhymes (Zhengyun) state the pronunciation is sao (rising tone). Explaining Characters (Shuowen) defines this as to abandon or discard. The character form derives from broom, indicating the use of a broom to clear away dust. Also, Broad Rhymes (Guangyun) states the pronunciation is sao (falling tone). Collected Rhymes (Jiyun), Dictionary of Rhymes (Yunhui), and Orthodox Rhymes (Zhengyun) state the pronunciation is zao (falling tone). Rites of Zhou (Zhouli), Office of the Earth, Gatekeeper section: In charge of sweeping the gate and courtyard. Book of Rites (Liji), Minor Rituals section: Large-scale sweeping is called sao; clearing the area in front of a seat is called pin. Commentary: Si-sao refers to sweeping floor mats; pin refers to removing filth. It also refers to protective structures for river embankments. Frames made of bamboo and wood are filled with willow branches and soil to resist water flow; this method was used in Yellow River engineering. Also, to rhyme with the following verse, it is pronounced sou (rising tone). Book of Odes (Shijing), Odes of Yong: Thorns grow upon the wall, impossible to sweep clean. This rhymes with the following words, dao and chou, where dao is read with a level tone.