A hamlet in Japan is a primary group of independent, small-scale agricultural producers' households. Within the hamlet, farm households arrange various problems satisfactorily each other. The most important role of the hamlet is to consolidate agricultural production infrastructure and rural life.

　The development of commerce and industry throughout the nation has increased the number of part-time farm households and changed the life style of farmers. Concurrently, the government has promoted the adjustment of the agricultural infrastructure in the past two decades. What have these changes brought about in hamlet's activities?

　In two hamlets which were studied, social activity was active before the Second World War, stagnant from 1946 to 1959, and became active again after 1960. Changes brought about by industrialization have made these hamlets more active, because they faced an increasing number of social problems. However, hamlet gatherings have become more specialized, with the members and agenda being limited. The method of consolidating agricultural production infrastructure has also changed. Before the War, the hamlets usually did this through their own efforts. After the War, the government has come to play a more prominent role in these matters than the hamlet.

　The hamlets have also increased their contacts with outside organizations. Hamlet headships are now held by middle class farmers as well as by upper class ones. However, the hamlet's management is supported by joint labor service and principle of reciprocity amongst farmers as before.

　The purpose of this paper is to grasp a recent trend of a paddy field rent. A paddy field rent is rising in recent years, but big-sized farms have leased in land more and more. Therefore, a rising trend of a rent could be characterized as materialization of differential of productivity between small-sized farms and big-sized ones.

　Main conclusions are as follows: First, it is shown that a rise of a paddy field rent is affected by institutional change such as amendment of the Agricultural Land Law in 1970. Secondly, it is presented that its rise is related to scale economy. Scale economy is mainly caused by completion of mechanization of rice cropping around in 1970. Consequently, big-sized farmers can pay to small-sized farmers the rent which is more than their income of inefficient rice cropping. After all, it can be said that Japanese agriculture has entered a new phase regarding tenant farming.

　The above recognition is derived from the following fact-findings: 1) It is statistically observed that the real price of rent and the proportion of rent to the yield have been increasing from 1965 to 1985. 2) It is shown that land rent is differing according to the beginning time of lease and also that rising trend of rent is mainly caused with abolishment of the restriction by revision of Land Law. 3) Finally, we compared three items: income of small-sized farms (S-income), surplus of large-sized ones (L-surplus), and rent. As the result, it is found that inequality such as S-income≦rent＜L-surplus has been realized in some region and is now being realized in another regions.

　Establishing water markets is very important for achieving efficient allocation of water resources. However, this situation is apparently not being achieved in California at the present time.

　To establish orderly water markets, it is necessary to solve the following problems:

　1) Legal uncertainties surrounding the current system of non-quantified water rights. To encourage water rights' holders to quantify their water rights, quantification costs should be decreased.

　2) Water pricing policy problems originating in the management of Federal Water Projects and the State Water Projects. a. Water tolls should be charged on the basis of each contractor's actual water use. b. Water pricing policies should be improved so that individuals possessing water rights can make profits through water transfers.

　3) Problems originating in water districts' water pricing policies. When a district transfers water to the outside, the allocation rule for water transfer revenues should be clearly defined so that transferors can get rewards depending on how much water they transfer.

　4) Lack of institutional arrangements associated with water transfers in dry years. Water institutions should be improved so that transferors and transferees can expect economic merits and demerits even in dry years.

　State water laws, Federal Water Projects' water pricing policies, State Water Projects' water pricing policies, and water districts' water pricing policies, all need to be organized into a total package system of water resources use. Therefore, all laws and policies should be co-ordinated with each other so that each can play a role in a larger water use system.