THE SEVEN HUNDRED YEAR PERIOD IN THE CLIMATE AND 

 THE AURORA BOREALIS IN JAPAN 



By Hideo Nishioka, Keio University, Tokyo 



In 1935 Professor Shida, of the ^Kyoto University, first brought the 

 700-year wave of chmatic change to hght on the annular rings of what 

 we call BENIHI, a kind of cypress about 1,050 years old which grows 

 on Mount Ari-san, Formosa. It was, however, not clear whether this 

 wave existed or not in Japan proper. In 1946 I received a report on the 

 annular rings of a Japanese cypress of about 810 years' growth at Nagano 

 Prefecture, which was measured by Mr. K. Yamazawa, and also I have 

 measured the annular rings of old columns of Horyu-ji Temple, Nara 

 Prefecture, and of old cedar on Mount Koya, Wakayama Prefecture, 

 of old Zalkova acuminate at Utsunomiya City, Tochigi Prefecture, and 

 so on. 



Fig. I. — The wave of 700 year periodic change of climate in Japan 



According to these measurements, the fact that a 700-year wave 

 definitely exists in Japan has been discovered. It was, however, about 

 two centuries behind that of Formosa — that is, the peak of the wave 

 means the warm periods in Formosa occur in the tenth century and the 

 seventeenth, but in Japan' it is in the ninth and the fifteenth. This 

 difference — viz., about two centuries — between the southern and northern 

 districts will suggest some secrets which probably have relation to the 

 fundamental reasons for both of the 700-year climatic changes. At any 

 rate, it is beyond doubt that the 700-year wave of climatic change has 

 occurred not only in Formosa, but in Japan. I therefore continued to 

 pursue further research in this climatic phenomenon. Such a great change 

 of climate marked on annular rings must bring many other historic proofs, 

 and I could fortunately find several points of evidence in many classics, 

 in archaeological discoveries and from botanical and zoological points 

 of view, all of which are shown on the diagram of Fig. 1 and included 

 in its explanation. 



(A) Shell-fishes {Anadara granosa Linne and Sanguinolaria- olivacea 

 Jay) and fishes {Muraenesox cinereus. Fofskal, Tylosuriis anastomella 

 Cuvier and Valenciennes and Tarns tmnifrons Temminck and Schlegal) 

 living in warmer water than there is at present in Tokyo Bay were taken 

 l^y the Stone age people for sustenance and formed the shell-mounds 

 of Shimogumi, Shimokuchi, Kayama, Moroiso in Kanagawa Prefecture 

 and other places. 



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