New signage has officially named this the Pangyo Climbing Wall.
15 m tall wall shaped like an arch. About a dozen routes from vertical to pure roof. Great anchors on every route. This spring perma-draws were added on the roof sections. A few marked routes from 5.10a to 5.11c? (Most of the ratings are not marked.)
Go out Exit 2 of Pangyo Station. Cross to the east side of the road and catch the either the R4000 or B380 bus. After the bus crosses the highway it will take a 90 degree left. The wall is about 1/2 km down the road on the right side tucked way back from the road just before the Holy Flames Church.
The Pangyo Climbing Club is very active here during the weekdays. They even bring out floodlights to keep the climbing going after dark. Washroom with running water on site.
Routes are tagged meanwhile. Range from 5.9 to 5.12.
To get there you can also take subway to Moran station, take Exit 6 and hop on bus 350.
Google Maps says it's about 14 stops. You can recognize the stop to get off by passing a red church. The arch is right after it and the bus stop is directly at the arch.