Xu Collection, Middle Volume Radical: Rain (yǔ) 雹 Kangxi Strokes: 13 Page 1372, Entry 26 Ancient script. Pronounced pu (rising tone). Shuowen Jiezi (Explanation of Writing): It is rain that has frozen into ice. Record of Rites by Dai De (Da Dai Liji): The concentrated energy of the Yang becomes graupel, and the concentrated energy of the Yin becomes hail. Graupel and hail are manifestations of a single type of energy. Commentary: Yang energy manifests as rain, which is warm. When Yin energy presses close to it, they cannot integrate, and they strike against one another to form hail. This is why the Spring and Autumn Annals Commentary of Guliang (Guliang Zhuan) states: Hail is a sign of Yin energy forcing the Yang. Piya (Amplified Observations): Yin energy wraps around Yang energy to become hail. Shen Feng held that in ancient times, ice was stored to preserve Yin energy; if it were extremely cold, there would be no hail, because the Yang energy would have no place to be released, which is the cause of hail formation. The shape of hail resembles half a bead, and its grains appear in triangular form. Snowflakes appear in six-pointed star shapes, while hail forms a solid in triangular shape. Hail is the residue of ice and the beginning of natural transformation. It is said: Hail is the ice of rain. It is also said: The weather phenomena of the north include clouds, rain, hail, graupel, and snow. Book of Rites (Liji), Monthly Ordinances (Yueling): If one implements winter policies during the mid-summer season, it will hail and freeze the grain. Commentary: This is because the energy of the Zi (winter) season has encroached upon the current time. Yang energy forms rain, and Yin energy arises to force it, causing it to coagulate into hail. Zuo Commentary (Zuo Zhuan), Fourth Year of Zhao: When a sage is in power, there is no hail. Even if it occurs, it does not cause disaster. Yunhui Bu (Supplement to the Collection of Rhymes): In the region of the Tao River and Mount Min, hail is called white rain. It is also called hard-headed rain. In the 17th year of the Shaoxing era of the Song dynasty, hail fell in Lin'an, shattering the roof tiles of the Imperial Academy. In the academy, the word hail was avoided, so it was referred to as hard rain. Also pronounced pu (entering tone), with the same meaning. Textual Research: Piya: The shape of hail currently resembles half a bead. Adjusted according to the original text: currently resembles has been corrected to resembles currently.