Cognomen 久子 (Hisako 
, 久子 ) , globally, is a rare last name. The surname 久子 is characteristic of Japan, where it is a rare surname, Singapore, where it is a very rare surname, and Israel. Not in comparison with a country's population, it is commonest in Japan, China, and Indonesia. Much more frequently, 久子 is the forename as well as the last name.