That chart doesn’t prove much because there were a ton of confounding variables. The late 1940s were an extremely strange time for Japan due to multiple years of near famine, American occupation, new constitution, total reorganization of its industrial economy, etc., as well as the beginning of 4 decades of extreme economic growth, which is associated with lower fertility. Wikipedia even says that the “Western practice of ‘dating’ spread” implying it was not a thing before. All this had to have moved fertility in one direction or the other.
That chart doesn’t prove much because there were a ton of confounding variables. The late 1940s were an extremely strange time for Japan due to multiple years of near famine, American occupation, new constitution, total reorganization of its industrial economy, etc., as well as the beginning of 4 decades of extreme economic growth, which is associated with lower fertility. Wikipedia even says that the “Western practice of ‘dating’ spread” implying it was not a thing before. All this had to have moved fertility in one direction or the other.
Of course this isn’t a proof, but it’s the best explanation for the drop I heard so far.
To the person who disagree voted: I assume you know a better or equally good explanation for the drop?