(1) Interesting things about the Gwageo or national civil service examinations under the Goryeo and Joseon dynasties of Korea

- It was the only path to a position of rank, hence it plays a big part in In-hun's ambitions

(2) - Gwageo examinations were very important not only for an individual but for his family because a yangban (noble) family that did not produce a government official for four generations WOULD LOSE THEIR STATUS AS NOBLES.

(3) Seungho's intelligence and encyclopedic knowledge of the classics ((1)he's read their entire library (2) when he looked at In-hun's poem he knew immediately that it was plagiarized (3) the doctor's flashback told that he was the brightest in their region)

(4) could have guaranteed him a high-ranking post because of how he could've easily passed the exam but he made the deliberate decision to not take it (as hinted in his conversation with In-hun)
- The examinations were administered in 3 stages: an initial qualifying test (chosi)

(5) administered in the provinces (In-hun has already passed this and it is mentioned that he did really well) a 2nd examination (hoesi) conducted in the capital, Hanyang (which is why In-hun is going to Hanyang AND it is hinted that Seungwon is going there too)

and a 3rd examination (jeonsi) in the presence of the king

(6) SOURCE: https://en.wikipedia.org/wiki/Gwageo