Abstract
A further 172 determinations of the geomagnetic field strength in western Japan between 5000 B. C. to 1800 A. D., combined with previous results, indicate that the strength of the field was consistently weaker than at present between 5000 and 1000 B. C., it then rose to a peak at about 600 A. D., since which it has been declining, except for a brief rise around 1300 A. D. Chemical demagnetization was efficient at removing secondary chemical remanences, particularly from some of the older pottery.
