Hanja is the name for Chinese characters used in the Korean language. Approximately 70% of Korean vocabulary comes from hanja, and though the grammar of the two languages is completely different the effect of Chinese on its neighbouring countries has been strong, and this can be seen in the usage of hanja. Korean used to be written entirely in hanja until the invention of hangeul by King Sejong and his scribes, and even then hanja was mainly used until the end of World War II.
Hanja, though not used as often as before, is often used in important documents where precision is required. As an example of how Hanja can help to clear up ambiguity, here are all the homophones of the word 수도 (sudo):
- 修道 "spiritual discipline"
- 受渡 "receipt and delivery"
- 囚徒 "prisoner"
- 水都 "'city of water'" (e.g. Hong Kong and Naples)
- 水稻 "rice"
- 水道 "water works"
- 隧道 "tunnel"
- 首都 "capital (city)"
- 手刀 "hand-knife"
Those who know hanja are capable of finding the hanja written in a hangeul script, though the process can be time-consuming especially given the fact that most software in Korea does not recognize hanja compound words and thus the user is often forced to pick characters one at a time. Here is an example of Korean from the front of the Korean Wikipedia:
위키백과사전은 전세계 200여개 언어로 만들어 가는 인터넷 백과사전으로, 누구나 함께 할 수 있습니다. 2002년 10월에 시작한 한국어 위키백과서존에는 지금 15,981 개의 페이지가 있습니다.
And here are the same two sentences with the hanja-based words written in their original form:
위키百科辭典은 全世界 二百餘個 言語로 만들어 가는 인터넷 百科辭典으로, 누구나 함께 할 수 있습니다. 2002年 10月에 始作한 韓國語 위키百科辭典에는 至今 15,981 個의 페이지가 있습니다.