In order to make clear the appearance and drainage areas of cold air stream on the mountain slope before and after sunset, the microclimatological observations were carried out on the northeastern slope of Mt. Omatsu (1, 648.7m) in the north of Nagano Prefecture, during the period of Aug. 18-20, 1976. They were taken at seven points stationed between about 1, 250m and 1, 450m M. S. L. along the slope (Figs. 1, 2). The horizontal distance between the highest Station No. 1 (1, 450m) and the lowest No. 7 (1, 250m) is about 1, 600 m, and the average inclination is about 7°. The observations of the air temperature at the heights of 1.3m and 0.3m (by Assmann ventilated psychrometer), and the wind velocity and direction at the height of 1.0m (by photo-electronic wind vane and anemo-meter) were carried out every minute during the periods of 18h00m-20h00m Aug. 18 and 17h30m-20h00m Aug. 19 and 20, 1976 respectively. Air temperature difference between these two heights (1.3m and 0.3m above the ground) is defined as “the degrees of inversion”. The time transition of distribution of “the degrees of inversion” was analyzed to clarify the appearance and drainage areas of the cold air stream on the slope. The results of the observations are summarized as follows: (1) Grass temperature on the slope of Mt. Omatsu before and after sunset falls with altitude when the wind velocity is about 2_??_3m/s. These tendencies, however, are not found in case of light wind or calm. (2) Vertical distribution of grass temperature on the slope of Mt. Omatsu before and after sunset is estimated as Fig. 6. (3) “The degrees of inversion” is always positive at the Stations No. 3(1, 320m) and No. 5(1, 275m) respectively when the general wind velocities are less than about 3m/s. The weaker the general wind blows, the more “the degrees of inversion” increases. So far as the observations during this period is concerned, the extreme value of “the degrees of inversion” runs into+1.5°C. (4) The lowest grass temperature is found around the Station No. 1 (1, 450m). It is, however, pointed out that “the degrees of inversion” is negative at that station when the general wind is strong, on the contrary, is positive when it is weak. (5) The appearance and drainage areas of the cold air stream are defined as follows: Appearance areas: the area where (1) “the degrees of inversion” reaches greater than +0.5°C, (2) air temperatures at the height of 0.3m correlate positively with the wind velocities at the height of 1.0m, (3) “the degrees of inversion”, however, correlates negatively with the wind velocities at the height of 1.0m, and moreover, (4) there is a drainage area found downwards of the slope. Drainage area: the area where (1) “the degrees of inversion” is greater than+0.5°C, (2) air temperatures at the height of 0.3m have a negative correlation with the wind velocities at the height of 1.0m, (3) the wind velocities at the height of 1.0 m are less than 3.0m/s and (4) a fall-wind is observed.
These considerations lead to the conclusion that in the evening (17h30m-20h00m JMT) of Aug. 20, 1976 a cold air stream appeared around Station No. 3 (1, 320m) during the period of 19h00m-1 9h20m and spread downward to Station No. 5 (1, 275m) during 19h14m to 19h27m.

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It has often been said that during the period of rapid economic growth of Japan there is a noticeable shortage of toji, who are the leaders of dekasegi-sha (seasonal labor migrants), in sake-brewing industry. Dekasegi-sha in the sake brewing industry, led by toji, go to sake-brewing regions from rural areas.
There are few studies on the recent changes in the patterns of dekasegi-sha in the sake-brewing industry, and on the relationship between the social conditions in the rural areas from which dekasegi-sha come and the recent trends in the sake-brewing industry.
The purposes of this paper are to discuss the patterns of dekasegi-sha in the sake-brewing industry, to find important factors of the changes in the patterns, and to find the structure of supply and demand of dekasegi-sha in the sake-brewing industry.
The findings are as follows:
1. The main streams of dekasegi-sha in the sake-brewing industry were from rural areas in the Setouchi and Hokuriku regions to the sake brewing districts in the Kinki, Chugoku, and Kanto regions. From 1927 to 1973, the number of dekasegi-sha in the sake-brewing industry from Okayama, Yamaguchi, Hyogo, Aichi, Ishikawa, and Fukui prefectures decreased. During the same period, the prefectures that increased the number of dekasegi-sha in the sake-brewing industry were Iwate, Akita, Nagano, Yamagata, Fukushima, and Saga prefectures (Fig. 1). The change in the distribution of toji revealed three types: (1) increasing type (Iwate and Akita prefectures), (2) decreasing type (Niigata, Hyogo, and Ishikawa prefectures), and (3) near-extinguished type (Kyoto and Shizuoka prefectures) (Fig. 2).
2. The recent reorganization in the sake-brewing industry reduced the need of dekasegi-sha. The increasing employment opportunities for farmers who seek part-time jobs reduced the number of dekasegi-sha in the sake-brewing industry. The toji groups from Iwate prefecture are moving into the Kanto and Chubu regions, and the toji groups from Niigata prefecture are moving into the Chubu regions.

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