Polygamy has a long history in Japan dating back to the Heian period, where aristocrats were known to have multiple wives and concubines. However, with the rise of Confucianism during the Edo period, monogamy became the norm, and the Meiji Restoration in 1868 officially banned polygamous marriage. Although polygamous marriage is officially banned in Japan, there are some exceptions to this rule, such as if a man's first wife is unable to bear children or for certain religious groups like Muslims and Mormons. Polygamous marriages can have significant social, psychological, economic, and legal implications for families involved. As Japan becomes more modernized and adopts Western values, it is likely that the practice of polygamous marriage will continue to decline.