China Plain Seoulsup serves jjajangmyeon and Chinese course meals in Seongsu, near Seoulsup. The menu includes Daetongryeong Jjajang, seafood bokkeum jjajangmyeon, gultangmyeon, and handmade mandu, along with set courses. The dining room is large and clean, with full-length windows and a group room. The jjajangmyeon uses a deep chunjang sauce and chewy noodles, and the tangsuyuk has a crisp batter with juices intact.