I was over at the National Museum of Korea to see the Art in America Exhibition. The show was well thought out and had some great representative pieces from all over the country. I was especially happy to see some pieces from the Philadelphia museum of art. I remember seeing some of the pieces there when I used to visit in my younger days.
The building has very impressive architecture and I would highly recommend you make a visit. There is also a huge wing that houses their Korean collection.
National Museum of Korea
Address: 서울특별시 용산구 서빙고로, 137
Yongsan-gu, Seobingo-ro 137