Specifying the Date when Mizushima Haruo Calculated His "Pre-publication of the 1921-25 Prefectural Life Table," Based on Circumstances of Publication and Changes of Methods.

We examined the first appearing papers of a series of the Mizushima Prefectural Life Table and checked its publication history and the transition of manufacturing methods as a first step in order to examine the theory that life expectancy in Okinawa has been long from a long time ago. However, the Prefectural Life Table of 1921-25 was first published in 1960, and its original form (as the "Pre-publication of the 1921-25 Prefectural Life Table") was estimated to have been started after WWII and completed in 1952-1954, based on the publication history and the transition of the manufacturing methods. In our next publication we will examine the change in the self-recognition about the accuracy of data from Okinawa in the Mizushima Prefectural Life Table, and discuss its relationship to the "Okinawa Is a Traditional Longevity Prefecture" theory.