Military of the Han dynasty

Recruitment and training At the start of the Han dynasty, male commoners were liable for conscription starting from the age of 23 until the age of 56. The minimum age was lowered to 20 after 155 BC, briefly raised to 23 again during the reign of Emperor Zhao of Han (r. 87–74 BC), but returned to 20 afterwards. Some convicts could choose to commute their service by serving on the frontier. Conscripts trained for one year and then served for another year either on the frontier, in one of the provinces, or at the capital as guards. A relatively small minority of these conscripts would also have served in the cavalry division in the north, which was primarily composed of volunteers from families of superior status, or waterborne forces in the south. Conscripts were generally trained to arrange themselves in a formation five men deep, but actual practice on the battlefield could be flexible, with some commanders preferring ranks of up to 10 men deep. Implementation of daily best practices was also highly dependent on each commander, with some like Li Guang eschewing administrative details while Cheng Buzhi always kept his men in tight formations. After finishing their two years of service, the conscripts were discharged. During Western Han times, discharged conscripts could still be called up for training once a year, but this practice was discontinued after 30 AD. Certain nobles were exempt from military conscription. Those of ranks four to eight did not have to perform service in their locality, and those of rank 9 and higher had full exemptions. During the Eastern Han period, commoners were allowed to commute military service by paying a scutage tax. Professional and Semi-Professional Armies During the reign of Emperor Wu of Han, the standing army was significantly increased to face the military challenges presented by the Xiongnu during the Han–Xiongnu Wars and other opponents during the Southward expansion of the Han Dynasty. The number of cavalry forces was also significantly increased. The Han military by this time mostly favored longer-serving professional and semi-professional troops over troops that were regularly rotated and retired after a short length of service: Garrison troops and armies in the provinces and frontiers were often professional or semi-professional military colonists. These soldiers were stationed on the frontier and served in the military in return for a land allotment. This land was often in the frontier itself, and created a self-sustaining system where the soldiers and retired soldiers would be able to farm land that would produce the food that would feed their armies and local populace. The difference between military colonies and agricultural colonies was that the former provided regular military service as well as grain, whereas the latter only provided grain and/or taxes. During the time of Emperor Wu of Han, people of low reputation and/or low economic class who were initially conscripted often stayed in the military as a way to advance their social and economic status. This included paroled convicts, pardoned criminals, juvenile delinquents, etc. This created another subclass of professional or semi-professional troops that numbered at least 150,000 soldiers by 97 BC, making them a considerable percentage of the 500,000 to 700,000 troops that made up the Han standing army: The Northern Army was a professional, full-time military force responsible for guarding the outer perimeter of the capital since 180 BC. It originally consisted of eight regiments and around 8,000 troops, but was later reorganized from 31 to 39 AD into a smaller force of five regiments, around 4,200 troops. The five regiments were each commanded by a colonel: the colonel of garrison cavalry, the colonel of picked cavalry, the colonel of infantry, the colonel of Chang River, and the colonel of archers. A captain of the center inspected the Northern Army and their encampments. The Southern Army was established in 138 BC, consisting of 6,000 troops, to defend the imperial palace. In 188 AD, the Army of the Western Garden was created as a counterweight to the Northern Army. The total number of soldiers protecting the capital in the Eastern Han, amounted to some 20,000 soldiers. Officers Neither the Qin or Han armies had permanent generals or field commanders. They were chosen from court officials on an ad hoc basis and appointed directly by the emperor as the need arose. At times several generals were given control of expeditionary forces to prevent any one general from obtaining overwhelming power and rebelling. A general's stipends were equivalent or slightly below that of the Nine Ministers, but in the case of failure on campaign, a general could face very severe penalties such as execution. Smaller forces were led by a colonel (xiaowei) Logistics According to Zhao Chongguo who served in the first century BC, a force of 10,281 men required 27,363 hu of grain and 308 hu of salt each month, requiring a convoy of 1,500 carts for transport. One hu is 19.968 liters, meaning that each soldier required per month 51.9 liters of grain and 0.6 liters of salt. Another document at Juyan suggests 3.2 hu, or 63.8 liters, of grain. Maintaining a massive standing army and launching military campaigns was very expensive for the government of the Han Dynasty. The Han Dynasty government under Emperor Wu of Han had to create new taxes, impose government monopolies over salt and iron, and sell aristocratic ranks in order to obtain sufficient funding because the existing sources of government revenues were insufficient: Decline When imperial authority collapsed after 189 AD, military governors reverted to relying upon their personal retainers as troops. Due to the ensuing chaos of the Three Kingdoms period, there was no need for conscription since displaced peoples voluntarily enlisted in the army for security reasons. The end of the Han dynasty system of recruitment eventually led to the rise of a hereditary military class by the beginning of the Jin dynasty (266–420). ==Chariots and horses==