Many Japan-born Koreans were discriminated against for being “half-bloods” — i.e. not of full Japanese ancestry. Also, the year of the Horse in the fifth cycle of the Japanese lunar calendar, "hinoeuma" — every sixtieth year — were thought to be bad luck. Women born during those years would often claim to have been born in the previous or following year. The belief was so widespread that in 1966, according to the "Japan Statistical Yearbook", the birthrate in Japan took a 26% dip.