Query: Qin dynasty worked with currency.

Relevant passages:
Qin dynasty <=SEP=> The Qin dynasty was the first dynasty of Imperial China , lasting from 221 to 206 BC . Named for its heartland of Qin , in modern-day Gansu and Shaanxi , the dynasty was formed after the conquest of six other states by the Qin state , and its founding emperor named Qin Shi Huang , the First Emperor of Qin . The strength of the Qin state was greatly increased by the `` Legalist '' reforms of Shang Yang in the fourth century BC , during the Warring States period . In the mid and late third century BC , the Qin accomplished a series of swift conquests , first ending the powerless Zhou dynasty , and eventually conquering the other six of the Seven Warring States to gain control over the whole of China . It is also the shortest dynasty in Chinese history , lasting only 15 years with two emperors .   Far from monolithic and demonstrating a sophisticated political outlook , excavated Qin texts show a more pragmatic and eclectic approach than a reading of traditional accounts of Shang Yang would suggest . Qin administration was by no means purely punitive , and was not harsher than was generally prevalent at the time . The Qin were not doctrinaire . Though often anathema to Legalist philosophy , Confucianism and its values too coexisted with `` Legalism '' during the reign of the First Emperor . Qin administrative documents considered such matters as filial piety , and one circulated letter reads that `` The purpose of all standards ( fa ) ... is to teach and lead the people , rid them of dissoluteness and depravity ... and turn them toward goodness . ''   During its reign over China , the Qin sought to create an imperial state unified by highly structured political power and a stable economy able to support a large military . The Qin central government sought to minimize the role of aristocrats and landowners and have direct administrative control over the peasantry , who comprised the overwhelming majority of the population , and control over whom would grant the Qin access to a large labor force . This allowed for the construction of ambitious projects , such as a wall on the northern border , now known as the Great Wall of China . For years , local rulers built walls along China 's northern border to protect their villages from invaders , but Emperor Shi Huangdi decided to connect them . Three hundred thousand peasants and convicts were forced to work on this 1,400 mile wall .   The Qin dynasty introduced several reforms : currency , weights and measures were standardized , and a uniform system of writing was established . The Qin 's military was revolutionary in that it used the most recently developed weaponry , transportation , and tactics , though the government was heavy-handed and bureaucratic . An attempt to restrict criticism and purge all traces of old dynasties led to the supposed burning of books and burying of scholars later espoused by Confucians .   Despite its military strength , the Qin dynasty did not last long . When the first emperor died in 210 BC , a different son was placed on the throne by two of the previous emperor 's advisers , in an attempt to influence and control the administration of the entire dynasty through him . The advisors squabbled among themselves , however , resulting in both their deaths and that of the second Qin emperor . Popular revolt broke out a few years later , and the weakened empire soon fell to a Chu lieutenant , who went on to found the Han dynasty . Despite its rapid end , the dynasty influenced future Chinese empires , particularly the Han , and the European name for China is thought to be derived from it .