The gwageo (科擧) was the system for selecting state officials by examination. First introduced under King Gwangjong of Goryeo, it developed greatly in Joseon. For the yangban, Joseon's ruling class, passing the exam — the civil exam above all — was the key channel for preserving a family's standing. Since a house with no office-holders for several generations struggled to be treated as yangban, sadaebu families taught their sons the Confucian classics from an early age and groomed them for the exam.
Civil, military, and technical exams
The gwageo had three broad branches: the civil exam (munkwa), which chose civil officials on their command of Confucian learning; the military exam (mukwa), which chose military officers by martial skill and strategy; and the technical exam (japgwa), which chose specialist officials in interpretation, medicine, law, astronomy, and the like. Of these, the civil exam carried the greatest prestige, while technical-exam passers were mainly of jungin status.
An exam of many stages
For the civil track, candidates first passed the lesser exam (sokwa) to become saengwon or jinsa, then sat the greater exam — the munkwa — in the stages of preliminary (chosi), secondary (boksi), and palace (jeonsi) examinations. Ranks were settled at the palace exam held before the king, and the top scorer was called the jangwon. The regular exam, the singnyeonsi, was held in principle every three years, and special exams such as the byeolsi and jeunggwangsi were held on occasions of national celebration.
Open in form, narrow in fact
In law, any free-born person could sit the civil exam. But over long years, only those who could afford the time and cost to study the classics were realistically yangban households, and the descendants of secondary sons (seoeol) or of remarried women faced restrictions on sitting. It was open in form yet a very narrow gate in reality. Whether one passed through it was an important line dividing the yangban from those below.