in 735 a devastating smallpox epidemic, which eventually killed about one third of the japanese population, broke out on kyushu and subsequently spread north-east. while most victims were from the producer populace of western and central japan, by 737, the epidemic reached the capital at heijō-kyō (nara) causing death and terror among the aristocracy. emperor shōmu was spared, but by the 8th month of 737 ten officials of fourth rank or higher were dead, including the "fujiwara four". the death of their top figures and heads of the four fujiwara branches considerably weakened the influence of the fujiwara clan.