The Five Notes
The term refers to the five musical notes that rise in pitch, from gong (宫), shang (商), jue (角), zhi (徵), to yu (羽), which correspond roughly to the notes of 1, 2, 3, 5, and 6 in today’s numbered musical notation. When a zhi minus is placed before zhi and a gong plus after yu, this pentatonic scale becomes heptatonic. Such division of the musical notes gives rise to a variety of tunes. Although Chinese classical music based on a five-note scale does not vary that much, it retains the beauty of a simple, quiet, and lyrical style. As ancient refined music and folksongs were mostly based on a five-note scale, this term often referred to music in general.
Gao Jianli struck the zhu instrument. Jing Ke sang to the beat, uttering a zhi-minus note. Those who saw him off broke out in tears. (Strategies of the Warring States)
A riot of color makes one dizzy; discordant melody damages one’s hearing; plenty of food numbs one’s taste bud; hunting to excess causes one to lose control over oneself; and a valuable object tempts one into stealing it. Therefore, a sage, once having eaten enough, will not seek sensual pleasures. Rather, he will abandon the desire for material comfort and be content with living a simple life. (Laozi)
When silk threads of various colors are woven together, a beautiful piece of embroidery is created. When the five musical notes are properly arranged, a beautiful melody is composed. When the five emotions are forcefully expressed, a beautiful piece of writing is created. This is all too natural and obvious. (Liu Xie: The Literary Mind and the Carving of Dragons)