Unlike the standard written Chinese, which is logographic (each character representing a word or part of a word), Nu Shu is roughly phonetic, with each of its approximately 700 characters representing a syllable. Although some Nu Shu characters appear to have been derived from standard Chinese characters, most are unrelated.
In ancient Hunan, women were discouraged from learning Nan Shu-the "Man's writing", i.e. Chinese written language; Nu Shu was therefore invented and used secretly, carefully guarded from men. Often, the characters were disguised as decorative marks or as part of artwork. Although Nu Shu has existed for centuries, it was not known to most of the world until recently, due to the intense secrecy regarding the language.
Before the Cultural Revolution, it was customary to burn Nu Shu books during the author's funeral to comfort her in the next world. During the Cultural revolution, thousands of Nu Shu manuscripts were destroyed, partly due to the fear of secret languages and partly due to the mission (of Red Guards) to destroy old cultures. As a result, few Nu Shu manuscripts survived.
After the Chinese Revolution, literacy spread among women, and Nu Shu fell into disuse. At present only a handful of old women are capable of reading it. After Yang Yueqing made a documentary about it, the PRC government started to popularize effort to preserve this rare language.