It is wellknown, that a castle in Japan never had castle-walls enclosing its inhabitants as well as its warriors. But, these is on]y one exception, and that Is "Kogoishi" or an ancient Korean style hilltop fort. The characteristics of such a fort are that it had its stone walls surrounding hilltop and its vast outskirts, including flat ground, and spring water gates, which were constructed upstream with accumulated stones. Almost all of Japanese historians, archeologists and geographers have agreed that the fort like this was established in early 7th century in Northern Kyushu and Western Chugoku districts. This treatise aims to investigate the relations between the Korean style hilltop fort and Kokufu or the local capital, such as Sanuki (now Kagawa Pref.), Bingo (Hiroshima Pref.), Biichu and Bizen (Okayama Pref. ) in ancient Japan. As a result of investigation, it is clear that the forts located at the back of Kokufu, and that both of these were generally connected with each other by a smooth route. This fact does not always mean that the forts were built for the shelter of Kokufu' s inhabitants, though the fort and Kokufu coexisted at the same time. We have to take into consideration the following matters : there are many huge old mounds of the powerful clans, and the people residing thereby have had the similar legend ; e. g., one of the local powerful clans subjugated a demon and a harmful fish. Besides, Korean historian argued that it might have been constructed in 3-4 century in Korea and also in Japan. Considering these evidences, we should assume that some of these ancient Korean style forts had been built before the Kokufu was constructed. In other words, it may be safely concluded that the Kokufu plan seems to have been adopted from the Kogoishi or ancient Korean Style hilltop fort.
Purpose : To show how industrialization has altered land use in Fukuyama. Hiroshima Prefecture. Method : Land use maps made in 1945, 1957, 1967 and one compiled in 1974 from the field work by the author were compared. Changes in land use, especially that from agricultural to urban uses were noted. Results : Prior to World War II, industries [n Fukuyama occupied little land, and did little to alter the structure of this erstwhile castle town. Following World War II, post-war reconstruction, the development of new industries and the rapid growth of established industries, caused the urban area to expand. In 1966 the construction by Nippon Kokan, of a large iron and steel p]ant in the eastern part of Fukuyama, accelerated the rate of land use-change. The construction of two company-housing areas and the reclamation of approximately 10 million square meters of land from sea have contributed to the formation of a secondary urban center, six kilometers from the original castle town site. Other industrial areas have grown up near Fukuyama harbor and along the National Highway 2, Iinking the center of the city with the secondary center, centered upon Nippon Kokan. Later, residential housing lots have filled in the areas behind this industrial ribbon and completed the linkage of castle town and secondary center. Residential growth has taken place largely around the original core area. Agriculture on the Fukuyama Plain has declined rapidly to a point where today little agricultural land can be seen.
In this paper, the writer tried to analyse a study of the history of geography by Koji lizuka. The purposes of this study are : 1. What was the way and purpose of his study ? 2. What was the relation between them and the study he really made ? 3. How can we characterize him as a scholar ? As a result of this study, the writer has concluded as follows : 1. He says that in order to investigate into the theories of geography, one must study it critically in connection with the contemporary thought, and consequently one must work out one's own methodology. Thus one can be free from the preconceived idea and can contribute much to the development of geography. Mr. Koji lizuka failed to give any concrete conclusion in most parts of his assertion, as he often cited Lucien Febvre's La Terre et l'Evolution Humaine. 2. Meanwhile, he changed his mind to incorporate the historical economics into the geography, he came to realize the method by which one could adopt the geographical concepts in connection with the contemporary thought. It was by this method that he was able to push his study of the history of geography forward. Although he studied the contemporary thoughts, he did not study the social background. The writer is dissatisfied with him. And regardless of the study he really made approach, he emphasized the point mentioned in l above, as `one's own methodology'. He was influenced greatly by the Vidal de la Blache's theory, but he did not study it critically. It is contradictory to his opinion that the study of geography's history means reconsidaration of one's methodology. 3. The above fact, mentioned in 2, must be critically studied. It is felt that though lizuka's studies were worth appreciaing, but at the same time they lacked in originality.
The studies of migration are classified into the analyses of migration factors and the investigations of spatial movements of migrants. In the former study, known as push-pull theory, it has been discussed that migration occurs as a movement to keep the regional equilibrium of income level and employment condition. On the other hand, the study of the latter has been developed in connection with the gravity model in which many problems have appeared. The value of distance exponent n seems to be variable due to various sorts of movements, varying urban size of the destination and in connection with service areas of central places, while functional distance may be actually more useful than physical distance like Stouffer's intervening opportunity hypothesis. The mobility difference of inhabitants as a mass also should be taken into consideration. Though the migration model is Improved by considering these factors, another direction in the study also exists in its improvement where better understanding of migration movements is expected by adding other migration factors to the gravity model as G. Olsson and R.A.Hart have done. The author also attempts to find out a better explanation of migration intensity with multiple regression model by adding other migration factors to the distance which has been measured by road distance. As a case study the author selected Hiroshima prefecture and researched into the migration between Hiroshima city and other communities in the Prefecture. The correlation coefficient between gross migration intensity and distance in Fig. 2, ( r = -0.757, n =106) is considerably low as compared with its values of visiting patients ( r = -0.875), commuters (r = -0.872) and driving learners ( r = -0.871), though value of inpatients (r = -0.765) is similar to value of gross migration intensity. It suggests that gross migration intensity such as the case of inpatients to Hiroshima city is influenced by many other factors except distance factor. As shown in Fig. 2, the distribution of residuals between the actual values of gross migration intensity and the estimated values from gravity model in the formula (1) mainly indicates the active values in the northern part of the prefecture on the one hand, and the negative values in the coastal region on the other hand. The negative values are especially large in the southeastern part which is not included in the migration area of Hiroshima city. In the construction of multiple regression model the author has introduced the following migration factors X_2-X_7 into the formula. 1 ) Areal difference of income level should have effect on volume and direction of migration movement. Consequently the author took up per capita income in i-community/per capita income in Hiroshima city (1967) as X_2 factor and the employee ratio of primary industry (1970) as X_3 factor. The X_3 factor is often used as an alternative one, because it sharply indicates areal difference of living standard. 2) The commuting ratio from i-community to Hiroshima city (X_4) may be conversely correlated in job opportunity in i-community and its surrounding area. 3) Central place system affects the migration movement. If the distance is equal, few migrants will move to the service area of another central place. Therefore, gross migration ratio to Fukuyama, Onomichi, Mihara and Fuchu cities from i-community was considered as X_5 factor. 4) When i-community increases gross migration ratio to six metropolitan prefectures (X_6), it may decrease the contact with Hiroshima city. 5) Though the ratio of net migration from i-community to Hiroshima city (X_7) should be theoretically indifferent from the ratio of gross migration, the latter may become larger, the larger the former is.
Gion-cho is one of the rapidly urbanizing areas to the north of Hiroshima City. Urbanization of the area has begun since 1964 when National Highway 54 was constructed. Land use in this area has changed from paddy fields to residential housing. Thus, the population of Gion-cho has increased from 25, 812 in 1965 to 40, 352 in 1971. The authors surveyed the groundwater conditions in this area in order to clarify the relationship between groundwater quality and urbanization. Items surveyed were depth of water table, pH, RpH, and the electric conductivity. These survey were carried out on the 29th June, 1965 and the 1st July, 1972. The results are as follows: 1) Gion-cho is situated on the flood plain of the Ota and Furu Rivers and the aquifer of non-confined water is found in the upper sands and gravels. Figs. 2 and 3 show that the groundwater of Nishihara flows from the Yasu River and the Yagi irrigtion channel to the Ota and Furu Rivers. On the other hand, the river water of the Yasu River and the Yagi irrigation channel is polluted with sewage from the surrounding urbanized area. However, this seems to have little effect on the quality of water in the Ota and Furu Rivers. The difference in the groundwater table as- shown in the figures may be caused by the heavy precipitation in June of 1972. 2) The change from 1965 to 1972 in groundwater quality are shown in Table 3 and Figs 2 and 3. In Nishihara, the value of the electric conductivity increased during these seven years. The pollution of groundwater in this area was caused by the increasing urbanization together with inadequate treatment of sewage.