李朝期(1010-1225)紅河デルタ開拓試論 : デルタ開拓における農学的適応の終末(<特集>故水野浩一教授を偲んで)

Abstract

This essay describes the state of agriculture in the Red River Delta in the 11th and 12th centuries, and is the third part of a historical study of the reclamation of that delta from the first century to the nineteenth century which aims to explain the characteristics of Vietnamese socio-economic history in comparison with those of other Southeast Asian deltas. First, an analysis of the political map of the Red River Delta during the Ly dynasty indicates that it is improper to call this dynasty a "mini centralized empire, " since it ruled only the Red River Delta proper, while most of the highland areas were controlled by semi-independent native vassals of a different culture from the Vietnamese in the delta. Even in the delta, more than eight local military powers remained from the civil war age in the late tenth century. It is thus highly improbable that the Ly dynasty weilded sufficient power to mobilize labour from all over delta area to construct hydraulic engineering works for agricultural development. Second, the geographical bases of these local military powers can be classified as follows : (1) Quoc Oai Chau-lower terraces (2) Phong Chau-lower terraces and natural levees (3) Dai Hoang Chau-lower terraces and backswamps (4) Bac Giang-monadnock, natural levees and floodplain (5) Dang Chau and Khoai Chau-sandbank, natural levees and upper delta (6) Hong Chau-upper delta and western lower delta (7) Nam Sach-eastern lower delta (8) My Loc-backswamps, coastal complex and end of natural levees (9) the area under the direct rule of Ly dynasty-natural levees and floodplain Their distribution is shown in maps 7 and 10. Comparison of these two maps with map 11 of the previous paper [Sakurai 1980 : 619] indicates that the unification of local powers at the village level progressed to the provincial level in the 11th and 12th centuries. For example, Phong Chau province (Son Tay, Vinh Tuong and Phu Tho province) had 4 local military powers in the 10th century, while during Ly dynasty only one Phong Chau vassal occupied the same area. The west floodplain (Casier de Hadong) had been disputed by three military powers in the 10th century, while under the Ly dynasty this area was absorbed by the Ly court as a royal estate. Further, while no power was evident in the lower part of the west floodplain or in the upper delta in the 10th century, in the Ly period the former area was cultivated by the Ly court as another royal estate and the latter area was the domain of the Hong Chau power. Third, descriptions in Viet Su Luoc indicate the existence of man-made embankments, one in Bac Ninh province based on the natural levees and the floodplain complex, and another in Khoai Chau and Hong Chau based on the natural levees, the upper delta and the upper part of the lower delta. Analysis of these delta locations, however, suggests that the embankments were built to reinforce the natural levees against flood water at the outer bank of curves, and that they needed only the labour of several villages. Furthermore, a small horse-shoe embankment was apparently built in Hong Chau provice in the upper delta and the upper part of the lower delta, where Binh Giang-type villages are located. Fourth, these embankments would have served for tenth-month-rice cropping. In this period, most of the delta had been reclaimed by the introduction of fifth-month rice, which was harvested before the flood season, and thus agriculture in the west floodplain, the main domain of Ly dynasty, would not have required such embankments. Indeed, the chronicles give no record of embankments in that area. Fifth, the local political powers at the edge of the Red River Delta that were based on the control of transportation routes between the delta core area and the outside world were preserved and strengthened by the development of commercial relations in the South China Sea World. At the end of Ly dynasty, the Tran family, which had controlled the water routes of the lower Red Riv