<P> Chinese cities of the Song period became some of the largest in the world, owing to technological advances and an agricultural revolution . Kaifeng, which served as the capital and seat of government during the Northern Song (960--1127), had some half a million residents in 1021, with another half - million living in the city's nine designated suburbs . By 1100, the civilian population within the city walls was 1,050,000; the army stationed there brought the total to 1.4 million . Hangzhou, the capital during the Southern Song (1127--1279), had more than 400,000 inhabitants during the late 12th century, primarily due to its trading position at the southern terminus of the Grand Canal, known as the lower Yangzi's "grain basket ." During the 13th century, the city's population soared to approximately a million people, with the 1270 census counting 186,330 registered families living in the city . Although not as agriculturally rich as areas like western Sichuan, the region of Fujian also underwent a massive population growth; government records indicate a 1500% increase in the number of registered households from the years 742 to 1208 . With a thriving shipbuilding industry and new mining facilities, Fujian became the economic powerhouse of China during the Song period . The great seaport of China, Quanzhou, was located in Fujian, and by 1120 its governor claimed that the city's population had reached some 500,000 . The inland Fujianese city of Jiankang was also very large at this time, with a population of about 200,000 . Robert Hartwell states that from 742 to 1200 the population growth of North China increased by only 54% percent in comparison to the Southeast which grew by 695%, the middle Yangzi Valley by 483%, the Lingnan region by 150%, and the upper Yangzi Valley by 135% . From the 8th to 11th centuries the lower Yangzi Valley experienced modest population growth in comparison to other regions of South China . The shift of the capital to Hangzhou did not create an immediate dramatic change in population growth until the period from 1170 to 1225, when new polders allowed land reclamation for nearly all the arable land between Lake Tai and the East China Sea as well as the mouth of the Yangzi to the northern Zhejiang coast . </P> <P> China's newly commercialized society was evident in the differences between its northern capital and the earlier Tang capital at Chang'an . A center of great wealth, Chang'an's importance as the political center eclipsed its importance as a commercial entrepôt; Yangzhou was the economic hub of China during the Tang period . On the other hand, Kaifeng's role as a commercial center in China was as important as its political role . After the curfew was abolished in 1063, marketplaces in Kaifeng were open every hour of the day, whereas a strict curfew was imposed upon the two official marketplaces of Tang era Chang'an starting at dusk; this curfew limited its commercial potential . Shopkeepers and peddlers in Kaifeng began selling their goods at dawn . Along the wide avenue of the Imperial Way, breakfast delicacies were sold in shops and stalls and peddlers offered hot water for washing the face at the entrances of bathhouses . Lively activity in the markets did not begin to wane until about the evening meal of the day, while noodle shops remained open all day and night . People in the Song era were also more eager to purchase houses located near bustling markets than in earlier periods . Kaifeng's wealthy, multi-story houses and common urban dwellings were situated along the streets of the city, rather than hidden inside walled compounds and gated wards as they had been in the earlier Tang capital . </P> <P> The municipal government of Hangzhou enacted policies and programs that aided in the maintenance of the city and ensured the well - being of its inhabitants . In order to maintain order in such a large city, four or five guards were quartered in the city at intervals of about 300 yards (270 m). Their main duties were to prevent brawls and thievery, patrol the streets at night, and quickly warn the public when fires broke out . The government assigned 2,000 soldiers to 14 fire stations built to combat the spread of fire within the city, and stationed 1,200 soldiers in fire stations outside the city's ramparts . These stations were placed 500 yards (460 m) apart, with watchtowers that were permanently manned by 100 men each . Like earlier cities, the Song capitals featured wide, open avenues to create fire breaks . However, widespread fires remained a constant threat . When a fire broke out in 1137, the government suspended the requirement of rent payments, alms of 108,840 kg (120 tons) of rice were distributed to the poor, and items such as bamboo, planks, and rush - matting were exempt from government taxation . Fires were not the only problem facing the residents of Hangzhou and other crowded cities . Far more than in the rural countryside, poverty was widespread and became a major topic of debate at the central court and in local governments . To mitigate its effects, the Song government enacted many initiatives, including the distribution of alms to the poor; the establishment of public clinics, pharmacies, and retirement homes; and the creation of paupers' graveyards . In fact, each administrative prefecture had public hospitals managed by the state, where the poor, aged, sick, and incurable could be cared for, free of charge . </P> <P> In order to maintain swift communication from one town or city to another, the Song laid out many miles of roadways and hundreds of bridges throughout rural China . They also maintained an efficient postal service nicknamed the hot - foot relay, which featured thousands of postal officers managed by the central government . Postal clerks kept records of dispatches, and postal stations maintained a staff of cantonal officers who guarded mail delivery routes . After the Song period, the Yuan dynasty transformed the postal system into a more militarized organization, with couriers managed under controllers . This system persisted from the 14th century until the 19th century, when the telegraph and modern road - building were introduced to China from the West . </P>

Who played an important role in the government of china during the song dynasty