Basement gym that's been around for a long time. Their website has some of the best information (in Korea) of climbs in the area (and Seoraksan). There are some fitness machines, but mostly just a large bouldering area with varying overhangs.
W20,000 a month for membership. Climbing school and trips are available. A few members speak English.
Located in Nam-gu a block off of Munsuro. The gym is south of the County Prosecutor's Office (법원), and just across from Geumho/금호 apartments. It's west of the Ulju-gu office, east of Munsu Football Stadium. You could take a bus to the County Prosecutor's office (법원) stop, then head N one block. When you get off the bus, you should see a Millet shop (selling minimal climbing gear, mostly clothing and accesories). The door is well signed. It's in the basement.