Editing Grand Canal (China) (section)

===Sui dynasty===
[[Image:China-Grand canal, Sui and Tang.svg|thumb|right|300px|The Grand Canal, under Sui and Tang dynasties.]]
{{multiple image
| width             = 
| image1            = Sui Wendi Tang.jpg
| alt1              = Emperor Wen of Sui
| image2            = Sui Yangdi Tang.jpg
| alt2              = Emperor Yang of SuiRed cartouche
| footer           = [[Emperor Wen of Sui]], who launched the project of the Grand Canal (left), alongside his son [[Emperor Yang of Sui]], who completed the first stage of the project (right). Both paintings by Yan Liben.
| width1            = 175
| width2            = 165
}}
The reunification of China under the [[Sui dynasty]] (581–618) ended three centuries of chaos since the [[Upheaval of the Five Barbarians]], and the renewed political stability allowed both the thorough repair of existing canals and [[flood control in China|flood control]] systems as well as the construction of new canals. The primary consideration of the Sui canals was the need to tap into the expanding economic and agricultural resources of the [[Jiangnan region]] in the southeast to enrich the main Sui capital at [[Luoyang]] to the west and to supply the [[expeditionary warfare|expeditionary]] [[Army of the Sui Empire|Sui armies]] in the [[Goguryeo-Sui Wars]] to the northeast. The institution of the Grand Canal also obviated the need for army garrisons to become self-sufficient [[Tuntian|part-time militia-farmers]] while guarding the dry frontiers between China, [[Goguryeo]] and [[First Turkic Khaganate|Göktürk]].<ref name="ebrey cambridge 116"/>

A [[Dyke (embankment)|dike]]-building project in 587 along the Yellow River—overseen by engineer Liang Rui—established [[lock (water transport)|canal lock gates]] to regulate water levels for the canal.<ref name="needham volume 4 part 3 308"/> Double slipways were installed to haul boats over when the difference in water levels was too great for the [[flash lock]] to operate.<ref name="needham volume 4 part 3 308"/> Similarly, by the year 600, there were major buildups of [[silt]] on the bottom of the Hong Canal, obstructing river barges whose drafts were too deep for its waters.<ref name="needham volume 4 part 3 307"/> The chief engineer of the Sui dynasty, Yuwen Kai, advised the digging of a new canal that would run parallel to the existing canal, diverging from it at Chenliu ([[Yanzhou]]).<ref name="needham volume 4 part 3 307">Needham, Volume 4, Part 3, 307.</ref> The new canal was to pass not [[Xuzhou]] but [[Suzhou]], to avoid connecting with the Si River and instead make a direct connection with the [[Huai River]] just west of [[Lake Hongze]].<ref name="needham volume 4 part 3 307"/> With the recorded labor of five million people under the supervision of Ma Shumou, the first major section of the Grand Canal was completed in the year 605 and was called the Bian Qu.<ref name="needham volume 4 part 3 308">Needham, Volume 4, Part 3, 308.</ref>

The Grand Canal was fully completed from the years 604 to 609 under [[Emperor Yang of Sui|Emperor Yang]],<ref name="ebrey cambridge 114">Ebrey, ''Cambridge Illustrated History of China'', 114: "[…] the Grand Canal, dug between 605 and 609 by means of enormous levies of conscripted labour."</ref> first by linking his southern capital [[Yangzhou]] northwest to Luoyang by the '''Tongji Canal''' {{nowrap|(<small>[[traditional characters|t]]</small> {{lang|zh|{{linktext|通|濟|渠}}}},}} {{nowrap|<small>[[simplified characters|s]]</small> {{lang|zh|{{linktext|通|济|渠}}}},}} ''Tōngjì Qú''). He then proceeded to connect Yangzhou southeast to Suzhou and Hangzhou by the [[Jiangnan]] Canal and to connect Luoyang northeast to [[Goguryeo-Sui Wars|his wars]] with [[Goguryeo|Korea]] by the '''Yongji Canal''' {{nowrap|(<small>[[traditional characters|t]]</small> {{lang|zh|{{linktext|永|濟|渠}}}},}} {{nowrap|<small>[[simplified characters|s]]</small> {{lang|zh|{{linktext|永|济|渠}}}},}} ''Yǒngjì Qú'').<ref name="ebrey cambridge 115">Ebrey, ''Cambridge Illustrated History of China'', p. 115</ref> After this network's completion in 609, Emperor Yang was said to have led a flotilla of boats {{convert|105|km|mi|abbr=on|sp=us}}<!--miles or li?--> long from the north{{where|date=October 2023}}<!--Korean front or Luoyang?--> down to his southern capital at Yangzhou.<ref name="ebrey cambridge 116">Ebrey, ''Cambridge Illustrated History of China'', 116.</ref> This process again involved massive levies of conscripted labor<ref name="ebrey cambridge 114"/><ref>{{Cite book|last=Ebrey, P.B.|first=Walthall, A|title=East Asia: A cultural, social, and political history (third)|publisher=Wadsworth Cengage Learning|year=2014|pages=76|language=English}}</ref> and was detailed at length in the ''Record of the Opening of the Canal'' {{nowrap|(<small>[[traditional characters|t]]</small> {{lang|zh|《{{linktext|開|河|記}}》}},}} {{nowrap|<small>[[simplified characters|s]]</small> {{lang|zh|《{{linktext|开|河|记}}》}},}} ''Kāihéjì'').<ref name="needham volume 4 part 3 308"/>

At this point, the Grand Canal continued to use noncontiguous artificial channels and both canalized and natural waterways rather than presenting a single continuous manmade canal.{{Citation needed|date=August 2021}} However, running alongside and parallel to the course of the canals was an imperial roadway with stables maintained at regular intervals to support a rapid courier system. Enormous lines of trees were also planted along parts of the canal as windbreaks.<ref name="ebrey cambridge 116"/><ref name="needham volume 4 part 3 308"/>