10 circuits, 43 commanderies (都督府, dūdū fǔ), and 358 prefectures (州 and later 府, fǔ). In 733, Emperor Xuanzong expanded the number of circuits to 15 by establishing separate circuits for the areas around Chang'an and Luoyang, and by splitting the large Shannan and Jiangnan circuits into 2 and 3 new circuits respectively. He also established a system of permanent inspecting commissioners, though without executive powers. The Tang dynasty also created military districts (藩鎮/藩镇, fānzhèn) controlled by military commissioners (節度使/节度使, jiédushǐ) charged with protecting frontier areas susceptible to foreign attack (similar to the Western marches and marcher lords). This system was eventually generalized to other parts of the country as well and essentially merged into the circuits. Just as in the West, the greater autonomy and strength of the commissioners permitted insubordination and rebellion, which in China led to the Five Dynasties and Ten Kingdoms period. Circuits and Military Districts Commanderies and Prefectures Counties * Circuits established under Xuanzong, as opposed to Taizong's original ten circuits. ** Circuits established under Xuanzong by dividing Taizong's Jiangnan and Shannan circuits. Other Tang-era circuits include the West Lingnan, Wu'an, and Qinhua circuits. Circuits under the Liao, Song and Jurchen-led Jin dynasties The Liao dynasty was further divided into five "circuits", each with a capital city. The general idea for this system was taken from the Balhae, although no captured Balhae cities were made into circuit capitals. The five capital cities were Shangjing (), meaning Supreme Capital, which is located in modern-day Inner Mongolia; Nanjing (), meaning Southern Capital, which is located near modern-day Beijing; Dongjing (), meaning Eastern Capital, which is located near modern-day Liaoning; Zhongjing (), meaning Central Capital, which is located in modern-day Hebei province near the Laoha river; and Xijing (), meaning Western Capital, which is located near modern-day Datong. Each circuit was headed by a powerful viceroy who had the autonomy to tailor policies to meet the needs of the population within his circuit. Circuits were further subdivided into administrations called fu (), which were metropolitan areas surrounding capital cities, and outside of metropolitan areas were divided into prefectures called zhou (), which themselves were divided into counties called xian (). The Song dynasty abolished the commissioners and renamed their circuits 路 (lù, which however is still usually translated into English as "circuits"). They also added a number of army/military prefectures (州级军 zhouji jun, or simply 軍/军, jūn). Circuits