 The Portuguese attributed qualities like intelligence and industriousness to Chinese and Japanese slaves which is why they favored them more.Traits such as high intelligence were ascribed to Indians, Chinese, and Japanese slaves.In 1595, a law was passed by Portugal banning the selling and buying of Chinese and Japanese slaves due to hostility from the Chinese and Japanese regarding the trafficking in Japanese and Chinese slaves On 19 February 1624, the King of Portugal forbade the enslavement of Chinese people of either sex.