The aprocryphal texts of the Han period 漢 (206 BCE-220 CE) were commentaries to the Confucian Classics (jing 經) used to establish prophesies on the base of natural and supernatural phenomena recorded in the basic texts. Such phenomena were interpreted as an expression of Heaven's will towards the ruler and the state. Many of the texts are written in a mystic language hardly to understand. These commentaries were seen as filling threads (wei 緯) to the warp threads of the Classics (jing 經). The prognostication texts (chen 讖) were older than these "sideline" writings to the Classics.
The oldest mentioning of such prophesy texts (chen 讖) is laid into the reign of Duke Mu of the state of Qin 秦穆公 (r. 659-621). During the reign of the First Emperor of Qin 秦始皇帝 (r. 246/221-210) the magician Lu Sheng 盧生 might have been the first author of a chen text, a so-called tulu 圖錄 "chart record". The most popular apocryphal texts are the famous Hetu 河圖 "River chart" and the Luoshu 洛書 "Scripture from the River Luo" which were said to have been detected on the back of a turtle emerging from the Yellow River resp. on the flanks of a fabulous Qilin beast 麒麟 ("unicorn") coming out of River Luo. Both texts were actually constellations of different hexagrams interpreted by many scholars through the ages. From many titles of apocryphal classics it can be seen that charts, diagrams or symbols were involved in the interpretation of the Confucian Classics and constituted a crucial part of these books.
The oldest actual apocryphal classic texts are Fu Sheng's 伏勝 Shangshu dazhuan 尚書大傳, the "Large commentary to the Shangshu", and Dong Zhongshu's 董仲舒 Chunqiu yinyang 春秋陰陽, which is lost. From the time of Emperor Wu 漢武帝 (r. 141-87 BCE) on for virtually all Classics of the Confucian canon apocryphal texts appeared. Those are called the apocryphals to the seven classics (qijing wei 七經緯). Together with the above-mentioned Hetu and Luoshu and the apocryphals to the Lunyu there was a corpus of 81 chapters of such texts, of which that to the seven classics consisted of 36 chapters, the Hetu texts of 9, the Luoshu texts of 6 chapters, both types allegedly from the times from the Yellow Emperor 黃帝 down to King Wen 周文王 (11th cent. BCE) of the Zhou dynasty 周 (11th cent.-221 BCE), and 30 chapters of both types dating from the times of Confucius 孔子.
Other apocryphal texts of this corpus were called Shangshu zhonghou 尚書中侯, Luozuiji 洛罪極, Wuxingzhuan 五行傳, Shitui duzai 詩推度災, Fanlishu 氾曆樞, Hanshenwu 含神務, Xiaojing gouming jue 孝經勾命訣, Yuanshenqi 援神契, and Zachen 雜讖. At the end of the Han period, Xi Meng 郗萌 collected various prophesies basing on charts and compiled the Chunqiu zaiyi 春秋災異 in 50 chapters.
The philosophy behind those book is mainly derived from Yin-Yang thought and correlative thinking. Dong Zhongshu, for instance, thought that the style of rule was reflected in omina and portents sent down by Heaven. A good ruler was praised by the appearance of "phoenixes" and "unicorns", while a bad ruler attracted natural disasters and rebellion. In this respect the apocryphal commentaries are very important for the understanding of how people living in the Han period thought about cosmology and metaphysics. Chen texts were willingly adapted by rulers to introduce new reign eras, and the usurper Wang Mang 王莽 (r. 8-25 CE) even based the legal foundation of his government of such texts.
The same did Emperor Guangwu 漢光武帝 (r. 25-57 CE) on the restauration of the Han dynasty, when he justified his rule by spreading ominous charts predicting his accession to the throne. Confucius was deified, his words became that of a god, and there were even stories of his extraordinary appearance as a deity that had been sent down by Heaven like a messiah. The use of apocryphal texts became so popular that they even overshadowed the study of the proper classics. While the study of the apocryphals was called the "inner teaching" (neixue 内學) that of the classics was called the "outer teaching" (waixue 外學).
During the famous conference of Confucian professors in the White Tiger Hall 白虎觀 inner and outer teaching were even officially given the same status. Inspite of its popularity serious scholars like Huan Tan 桓譚, Yin Min 尹敏, Zheng Xing 鄭興, Zhang Heng 張衡 and, above all, Wang Chong 王充, opposed this unreflected kind of studying the apocryphal texts and criticised them as irrational and meaningless. Zhang Heng's request to prohibit such texts was declined. Apocryphals were only prohibited centuries later, in 460 CE.
Their popularity and practicality nevertheless helped them surviving into the Tang period 唐 (618-907), when it was still common to justify rule with forged texts containing prophecies, as under Empress Wu Zetian 武則天 who even had forged the Buddhist Mahāmegha Sutra (Datanjing 大曇經) to justify her reign. Even the Tang standard commentaries to the classics, the Jiujing zhengyi 九經正義, quote from the apocryphals. Ouyang Xiu 歐陽修 and Wei Liaoweng 魏了翁 (Jiujing yaoyi 九經要義) therefore revised the standard commentaries to the Confucian Canon and cleared away such quotations.
From then on the chenwei texts lost their high standing and were virtually forgotten, until the Ming period 明 (1368-1644) scholar Sun Jue 孫瑴 (Guweishu 古微書) and the Qing period 清 (1644-1911) scholars Yin Yuanzheng 殷元正 (Weishu 緯書) and Ma Guohan 馬國翰 started digging them out again for academic purposes. Ma Guohan assembled fragments of such texts in his reprint series Yuhan shanfang jiyi shu 玉函山房輯佚書, Huang Shi 黃奭 (Yishukao 逸書考) did the same in his reprint series Hanxuetang congshu 漢學堂叢書. Zhao Zaihan 趙在翰 published the collection Qiwei 七緯, and Qiao Songnian 喬松年 compiled a last collection of apocryphal texts, the Weiju 緯攟. A complete collection of surviving apocryphal texts has been published by the Japanese scholars Yasui Kōzan 安居香山 and Nakamura Shōhachi 中村璋八 called Isho shūsei / Weishu jicheng 緯書集成 (Tōkyō: Meitoku shuppansha, 1971). A second collection with the title of Weishu jicheng has been published in 1994 by the Shanghai guji press 上海古籍出版社.