Hanja (한자, 漢字) is the Korean word for Chinese characters. Hanja are Chinese characters that were borrowed and incorporated into the Korean language with Korean pronunciation. Hanja was used as early as the Gojoseon period under the first Korean kingdom. Although Koreans use Hangul, a writing system developed 500 years ago for the Korean language; Hanja is still used in conjunction with Hangul. Learning Hanja is optional for beginning Korean language students. However, because many Korean words come from Chinese roots, knowing Hanja can help master enough vocabulary to become fluent in Korean.