"Gyochukokyo" is a collection of commentaries on the "Kokyo" (Classic of Filial Piety) compiled by Genso (Emperor Xuanzong [Tang]). There were two kinds of Gyochukokyo, one being "Kaigenshichubon" (annotated edition by Genso), which was written in 720, and the other being Tenhojuchubon (revised edition of Kaigenshichubon), which was revised in 743 and distributed three years later; however, only the latter remains in existence. Single volume.
"Kokyo" had once disappeared as a result of the "Burning of books and burying of scholars" in Ancient China; however, two editions were rediscovered during the Former Han period, and were called 'Kobun' and 'Kinbun,' respectively, due to their font style. Commentaries were later added to 'Kobun' by Ko Ankoku (Kong Anguo) and to 'Kinbun' by Teigen (Zheng Xuan), and both became widely used.
However, there were suspicions that the books may be fake due to the circumstances in which they were rediscovered, and during the Tang Dynasty, two distinct schools were formed—the 'Kobun' school and the 'Kinbun' school—as a result of a difference in opinion regarding which was the authentic "Kokyo" book, with both accused the other of following a 'forged book.'
To remediate this problem, Genso brought together Confucian scholars of both schools and had them hold a debate, which ended with inconclusive results. As a distinguished scholar, Genso himself tried to settle the situation by forming an official commentary.
Genso believed the 'Kinbun' to be the base, and he wrote his commentaries while adopting those written by Ko Ankoku, Teigen, I Sho (Wei Zhao), and O Shuku (Wang Su). Genso believed that a ruler taking the lead in displaying filial piety is able to stabilize the country, and that retainers are obliged to emulate the lord's behaviors, so he placed particular emphasis on 'Kuntoku no Kanyo' (fostering of virtue) and 'Shuju no Funbetsu' (categorization of master and servant). This is the main reason why his edition has been regarded as the 'Tenshi no sho' (the Emperor's book).
After distribution of this edition, all lectures and commentaries of "Kokyo" followed suit, and conventional commentaries became obsolete.
Although the commentary of this edition had 2,800 characters in total, and had more than Teigen's 2,000 characters, it was much fewer than Ko Ankoku's, which was about 8,800 characters, and was far from being an adequate commentary. Therefore, Kei Hei (Xing Bing), who received an order from Shinso (Zhenzong) (Song) of Northern Song Dynasty, created the chuso ('Jusankyo chuso' [annotation and interpretation learning of Thirteen Classics]) and named it "Kokyoseigi."
In Japan, on November 6, 860, with an appeal by Daigaku hakase (university professor) OKASUGA no Otsugu, a Mikotonori (imperial edict) was issued to use the "Gyochukokyo" for commentaries of the "Kokyo" henceforth, and not to use the commentaries by Ko Ankoku and Teigen that had been set under the school's order. Prior to this, from March of the same year to January of the next year, OKASUGA no Otsugu gave lectures on "Gyochukokyo" to the 12-year-old Emperor Seiwa. It is believed that FUJIWARA no Yoshifusa and OKASUGA no Otsugu adopted this edition with the purpose of giving government officials an official education to foster allegiance to the Emperor, as well as to foster "Kuntoku no Kanyo" in the young Emperor Seiwa, thereby tried to overcome the instability of political foundation, which was caused by the enthroning of the infant Emperor Seiwa, with the help of the political power of his maternal grandfather, FUJIWARA no Yoshifusa, against public opinion that pushed for his paternal older half-brother, Imperial Prince Koretaka. However, in the Mikotonori, the commentaries by Ko Ankoku that were used as a literary reference, such as in Chinese poetry, were permitted to be continually used in education other than that of Emperors and the Imperial Family, which supports the fact that this adoption was only to seek political advantage and did not even gain support of the whole Daigakuryo (Bureau of Education under the Ritsuryo system).