Someone who reached the top of Nojeok Hill recently left the following tag at the top. Here's what it says:
Seoul, Gwangjin – Moon Jeong-Nam
The Nation's 4,000 Mountains and Hills
In Commemoration of Reaching the Summit
I'm not 100% certain about the situation here, but it appears that someone named Jeong-Nam Moon who lives in the Gwangjin area of Seoul is systematically climbing mountains and hills across Korea and leaving tags like this at the top of each one. Apparently there is a list somewhere of the top 4,000.
I'm not sure if he's marking Nojeok Hill as the 4,396th hill/mountain he's climbed or if Nojeok Hill is registered as Mountain #4396 in some directory.
Either way, for a country the size of Korea to have so many hills and mountains gives you an idea of how mountainous the place is!