Gamjagol (감자골 in Korean; ガムザゴル in Japanese) is a Korean restuarant that we've been to a number of times to eat gamjatang. It's not far from Seibu-Shinjuku station and Kabukicho (three to five minutes on foot).
Gamjagol has many reminders of the Korean-boom plastered across its walls and windows. All the famous faces of Korea's cross-border cultural infusion can be found on various posters and digital printouts that seem to grow both in variety and the amount of wall space that they cover (the walls of the toilets are now decorated as well!).
According to the photos on the walls, Yomiuri Giants first-baseman Lee Seung-yeop has been to the place at least a couple of times. I'm sure that he agrees that this place has good eats.
We routinely get a bowl of dongdong-ju (a type of milky rice-wine) with our gamjatang (potato and pork stew). The stew boils in front of you on a burner that is built into the center of the table. Like many Korean restaurants in the Shin-Okubo area, Gamjagol does Korean food proud, and the bottomless bowls of side dishes (kimchi!) are enough to fill you up before the main course even arrives.
Gamjagol is on the second floor of the building (only a stone's throw from the Shin-Okubo Don Quijote), and one feature that might take some by surprise is that a menu from the restuarant downstairs also sits on the table.
The restaurant downstairs is a chicken joint, and you can have them deliver a plate of yangnyeom fried chicken to your table on the second floor.
I don't recommend calling Domino's to deliver a pie to your table, but that's kind of the same idea. The people downstairs will bring it right up! We often get a plate of chicken to nibble on while we're waiting for our gamjatang to cook (be sure to stir it occasionally).
The vat of veggies and pork above is how gamjatang looks when it's first delivered to the table. You can eat well and have a couple of drinks for 3,000 to 4,000 yen.
For more pictures of the place click here.