When we were in the market, it took us about 15 mins to find it, we asked at least 5 Korean to point us where its location. We passed back and forth the restaurant. No signs or indication that it is found in a hidden alley. Here is the picture of the alley, you can see why we can miss it easily.
In front of the restaurant, you can see a woman making large mandu skins.
Two popular dishes make this restaurant famous : manduguk (mandu in a soup) and haemul pajeon (seafood pancake).