Japan had an official slave system from the Yamato period (3rd century A.D.) until Toyotomi Hideyoshi abolished it in 1590. Afterwards, the Japanese government facilitated the use of "comfort women" as sex slaves from 1932 – 1945. Prisoners of war captured by Japanese imperial forces were also used as slaves during the Second World War. The export of a slave from Japan is recorded in 3rd century Chinese historical record, but it is unclear what system was involved, and whether this was a common practice at that time. These slaves were called seikō (生口 "living mouth"). In the 8th century, slaves were called Nuhi (奴婢) and laws were issued under the legal codes of the Nara and Heian periods, called Ritsuryousei (律令制). These slaves tended farms and worked around houses. Information on the slave population is questionable, but the proportion of slaves is estimated to have been around 5% of the population. Slavery persisted into the Sengoku period (1467–1615) even though the attitude that slavery was anachronistic seems to have become widespread among elites. In 1590, slavery was officially banned under Toyotomi Hideyoshi; but forms of contract and indentured labor persisted alongside the period penal codes' forced labor. Somewhat later, the Edo period penal laws prescribed "non-free labor" for the immediate family of executed criminals in Article 17 of the Gotōke reijō (Tokugawa House Laws), but the practice never became common. The 1711 Gotōke reijō was compiled from over 600 statutes promulgated between 1597 and 1696. After the Portuguese first made contact with Japan in 1543, a large-scale slave trade developed in which Portuguese purchased Japanese as slaves in Japan and sold them to various locations overseas, mostly in Portuguese-colonized regions of Asia such as southern China and Goa but including Argentina and Portugal itself, until it was formally outlawed in 1595. Many documents mention the large slave trade along with protests against the enslavement of Japanese.