Korea has a system to manage the immigration and period of sojourn of foreigners, of which requirements for sojourn refer to the social activities or personal status the foreigner can assume during his stay in Korea. They are therefore a standard for managing the sojourn of foreigners.So if a foreigner entering Korea meets specific requirements, he or she is guaranteed sojourn in Korea as long as he or she maintains the authorized activities or personal status. However, if the person?s circumstances have changed or engagement in other activities is planned, the foreigner must apply for a visa of another type corresponding to his or her desired activities or status.In general, countries define sojourn requirements and apply the appropriate visa to the requirements in order to facilitate the management of foreigners entering the country. Thus, with the issue of the visa, the conditions for sojourn are given at the same time (‘one-time inspection’). There exists also the “double inspection”, which means that the visa is only an entry inspection, and the immigration inspector will issue separate sojourn permission. Korea falls into the former category of a “one-time inspection”.Accordingly, the Korean visa contains both, the sojourn conditions and requirements as well as the sojourn period. Thus, the foreigner is permitted to stay in Korea during that period under the given conditions. If the foreigner wishes to engage in employment in Korea, a C-4 visa or an E-range visa has to be issued. Work is only permitted in the designated workplace.The requirements and conditions for sojourn are composed of alphabetic letters and numbers (ex. A-1). There are presently 34 types of visas according to Art.12 (appendix 1) of the Enforcement Decree of the Immigration Control Act.Korea distinguishes between short-term sojourn (less than 90 days) and long-term sojourn (91 days and longer). Foreigners who wish to stay longer than 91 days in Korea have to apply for alien registration within 90 days of the date of their entry