Japanese prefecture could adopt an ordinance to make the age of consent be 18 instead of 13 ,there is 47 prefecture in Japan ,12 prefecture did the ordinance in the 1950's ,19 did it in the 1960's (31/47 prefecture) ,13 in the 1970's (44/47) and 2 in the 1980's (46/47) ,the last one (Nagano...