Quick questions on The Han dynasty economy: agriculture, monopolies, coinage and the Silk Road: HSC Ancient History

Agriculture was the foundation on which everything else in the Han economy rested. The great majority of the population were peasant farmers working small household plots, chiefly on the North China Plain and in the Wei and Yellow River valleys.

Emperor Wu replaced the older, inconsistent banliang coinage, much of it minted privately or by regional kingdoms and prone to debasement and counterfeiting, with a new standard coin in 118 BC: the wuzhu, meaning "five zhu", named for its weight standard. From 113 BC the government withdrew minting rights from kingdoms and commanderies entirely and centralised production at the Shanglin sanguan, the three mint offices attached to the imperial Shanglin park near the capital, Chang'an. This was a fiscal reform and a political one at once: it removed an independent source of income and influence from regional princes at a time when the central court was already wary of their power. The wuzhu standard proved remarkably stable, remaining China's basic coin for more than seven hundred years.

From 138 BC the imperial envoy Zhang Qian was sent west, initially to seek an alliance against the Xiongnu; although the alliance failed, his reports on Central Asia, and a further mission from 119 BC, gave the Han court its first detailed knowledge of the kingdoms and trade routes of the region. Along the resulting network of overland routes, later called the Silk Road, Han China's most famous export moved west: silk, prized enough that some Roman writers later complained of the drain of precious metal spent acquiring it. In the other direction came horses, prized above all the "heavenly horses" of Ferghana, sought partly to strengthen Han cavalry against the Xiongnu, together with jade, glass and other goods. Protecting and administering this trade, alongside diplomatic and military aims, was one reason the Han extended garrisons and, from 60 BC, appointed a Protector General of the Western Regions to oversee Han interests along the route.

Confucian reformers looked back to the jingtian, or "well-field", system, an idealised model, described in the Warring States text Mencius (3A.3), in which a square of land was divided into nine plots in a pattern resembling the character for "well" (井): eight households farmed their own outer plot and jointly worked the shared central plot, whose yield went to the state instead of individual tax. Whether the well-field system ever operated exactly as described is uncertain and debated by modern scholars; what matters for the Han is that it functioned as a powerful ideal of fair, communal landholding. Around the reign of Emperor Wu, the scholar-official Dong Zhongshu invoked the well-field ideal to argue for limiting the size of private landholdings and curbing the growing power of great landowners, but his proposal was not adopted as policy.

Iron ploughshares, replacing wood and stone, spread widely under the Han, cutting deeper furrows with less effort, and increasingly these ploughs were drawn by oxen rather than pulled by people. In the later part of Emperor Wu's reign, the official Zhao Guo promoted the "alternating fields" method (daitian fa), rotating strips of cultivated and fallow land within the same field each year to rest the soil, together with an improved multi-share plough, drawn by a pair of oxen and worked by a small team, that could furrow and sow in a single pass. The Hanshu's "Treatise on Food and Money" (Shihuo zhi) records that the government sometimes loaned iron tools and oxen to poorer households so the new methods could spread beyond wealthier farmers.

Later Han sources credit an official named Bi Lan with a square-pallet chain pump, a looped chain of small wooden pallets running over two wheels that scooped water upward, first recorded in the AD 180s under Emperor Ling lifting water to sprinkle the streets of the capital, Luoyang, and subsequently adapted to lift irrigation water above a river or canal's own level onto higher fields, extending cultivable land beyond what gravity-fed channels alone allowed.

In 54 BC, on the advice of the Grand Minister of Agriculture, Geng Shouchang, the Han government under Emperor Xuan established the changping cang, or "ever-normal granary": a state-managed grain reserve that bought surplus grain cheaply after harvest and sold it back into the market when prices rose during shortage, evening out price swings for both farmers and consumers and, in principle, protecting peasants from distress selling and reducing merchant speculation in grain.