This study examined the structure of the Sengoku period castle-town in Kuroiwa, Tosa province, by referring to the spatial data recorded in Chôsokabe Cadastral Books. In conducting these analyses, I investigated the land tenure areas, which belonged to the entitled members in the market town and the retainers, in the territory of local lords (kokujin) and then examined by the attributes of homesteads. In addition, in examining the structure of land tenure which belonged to the retainers in Kuroiwa Castle-Town, I noted the attributes of land tenure areas which belong to the retainers and small hamlets in the territory of kokujin.
These examinations revealed the following. With regard to the structure of market town, the homesteads of the entitled members in the market town who were engaged only in commerce and those who were engaged in both commerce and agriculture were partially concentrated, and groups of these two types were dispersed each other in the market town. For the structure of retainer homesteads, the homestead of a highest-ranking retainer was adjacent to the guarded homestead (doi) that was smaller than castles.
Regarding the structure of retainer land tenure in Kuroiwa Castle-Town, Ukon Kataoka, who was a highest-ranking retainer, had land tenure in fifteen small hamlets, including a small hamlet named Yamamoto, with his largest percentage of land tenure. The percentage of land tenure in Kuroiwa, a small hamlet, was just 6.7 percent of his land tenure. In contrast, fifth-rated retainers had land tenure in one to three small hamlets, and the small hamlet Kuroiwa's percentage ranged from 49.2 to 100 percent of their land tenure.
It is conceivable that the entitled members in the market town who owned cultivated land spanning across more than 10,932 m² （1chô) could accumulate cultivated land due to their prosperous commercial activities. The reason the homestead of a highest-ranking retainer was adjacent to the guarded homestead (doi) was probably that Chôsokabe became more powerful as feudal lords. This increase in his power can be seen from land surveys in the level of feudal lord area and castle abandonments after Chôsokabe had become subject to the reign of Hideyoshi Toyotomi. Kataoka, a kokujin, increased his power in the local lord's territory along with Chôsokabe's increase of power.

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The relationship between the enhanced convective regions in tropics and the change in geopotential height fields around Japan at the end of Baiu is investigated.
Based on outgoing longwave radiation (OLR) values around Japan, the 20 years when the withdrawal of Baiu was obvious are selected out of 24 years from 1979 to 2002, excluding 1982, 1993, 1998, and 2000, and end-days of the Baiu season are defined for each of the 20 year. Daily time series of OLR and geopotential heights at 850 hPa, 500 hPa, and 200 hPa are respectively composited with respect to the end-day of 20 years. A comparison between the composite maps of OLR before and after the end of Baiu reveals that the patterns of the changes in circulation are divided into four groups:1) enhanced convection in both the western North Pacific and the Philippines (type WP, 2 years）;2) enhanced convection only near the Philippines (type P, 7 years）;3) enhanced convection only in the western North Pacific (type W, 5 years）;and 4) no enhanced convection in either region (type N, 6 years).
Composite analyses of the geopotential height fields are performed for the pattern of types P, W, and N, respectively, and it is clarified that three main mechanisms described below cause the end of the rainy season:（1) the strengthening of the anticyclone around Japan as a result of the propagation of stationary Rossby waves from the tropical region and along the westerlies (type-P）;（2) the strengthening of the anticyclone around Japan as a result of the propagation of stationary Rossby wave along the westerlies (type-N）;（3) the eastward retreat of the Pacific High (type-W).
The changes of geopotential height fields before and after the end of Baiu in types P and N suggest that the propagation of stationary Rossby waves strengthen the Pacific anticyclone near Japan. It is suggested that the differences of the domains where convection was enhanced are related with the generation of stationary Rossby waves which act as the trigger for the end of Baiu.

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