Iwongu Gupo Guksi is a noodle shop inside Gupo Market in Busan that serves on-guksu and bibim-guksu. It uses an anchovy broth and offers on-guksu, bibim-guksu, gao-ri hoe bibim-guksu, and gimbap. A line forms at lunchtime, but the tables turn over quickly. The bibim-guksu is a little spicy for mild palates.