contributed to the decline in the number of nobi to about 1.5% of the total population by 1858. The hereditary nobi system was officially abolished around 1886–87, and the rest of the nobi system was abolished with the Gabo Reform of 1894. However, slavery did not completely disappear in Korea until 1930, during Imperial Japanese rule. During the Imperial Japanese occupation of Korea around World War II, some Koreans were used in forced labour by the Imperial Japanese, in conditions which have been compared to slavery. These included women forced into sexual slavery by the Imperial Japanese Army before and during World War II, known as "comfort women". After the Portuguese first made contact with Japan in 1543, slave trade developed in which Portuguese purchased Japanese as slaves in Japan and sold them to various locations overseas, including Portugal, throughout the 16th and 17th centuries. Many documents mention the slave trade along with protests against the enslavement of Japanese. Japanese slaves are believed to be the first of their nation to end up in Europe, and the Portuguese purchased numbers of Japanese slave girls to bring to Portugal for sexual purposes, as noted by the Church in 1555. Japanese slave women were even sold as concubines to Asian lascar and African crew members, along with their European counterparts serving on Portuguese ships trading in Japan, mentioned by Luis Cerqueira, a Portuguese Jesuit, in a 1598 document. Japanese slaves were brought by the Portuguese to Macau, where they were enslaved to Portuguese or became slaves to other slaves. Some Korean slaves were bought by the Portuguese and brought back to Portugal from Japan, where they had been among the tens of thousands of Korean prisoners of war transported to Japan during the Japanese invasions of Korea (1592–98). Historians pointed out that at the same time Hideyoshi expressed his indignation and outrage at the Portuguese trade in Japanese slaves, he was engaging in a mass slave trade of Korean prisoners of war in Japan. Fillippo Sassetti saw some Chinese and Japanese slaves in Lisbon among the large slave community in 1578, although most of the slaves were black. The Portuguese also valued Oriental slaves more than the black Africans and the Moors for their rarity. Chinese slaves were more expensive than Moors and blacks and showed off the high status of the owner. The Portuguese attributed qualities like intelligence and industriousness to