Chou Collection, Upper Volume Radical: Mouth (kǒu) Ku Kangxi strokes: 20 Page 214, Entry 01 According to the Tang Rhyme (Tangyun), the collection of rhymes (Jiyun), and the compilation of rhymes (Yunhui), the pronunciation is ku. As stated in the Explanation of Simple and Compound Characters (Shuowen), it refers to an urgent or extreme report. Additionally, according to the Records of the Grand Historian (Shiji), Record of the Five Emperors, Emperor Ku Gaoxin was the great-grandson of the Yellow Emperor. According to the collection of rhymes (Jiyun), it is also written in a variant form (ku). According to the Records of the Grand Historian (Shiji), Table of the Three Dynasties, Emperor Ku was the great-grandson of the Yellow Emperor.