Udon restaurant in Dongjak: cold tenbukkake vs warm kitsune at Kosi

There's a surprising amount of food along the alleys near Exit 9 of Isu Station, and I finally came back to a go-to spot for when I want something light like udon or tonkatsu. Kosi Isu Branch is known for house-made udon noodles and hand-breaded tonkatsu, and on a muggy hot day I made sure to eat plenty of cold udon.

Where is Kosi Isu Branch, and which Isu Station exit?

Kosi Isu Branch is close to Exits 7, 8, and 9 of Isu Station. Naver Maps points you to Exit 9, but the elevator there is under construction right now, so I'd recommend coming out Exit 7 or 8 and walking around instead. It sits just off the main road down a quiet alley, which makes the Kosi alley feel even calmer.

The wooden sign and soft lighting give it the feel of a udon shop tucked into a back alley in Japan, so the exterior alone sets a good mood.

Right at the entrance a sign reads "house-made noodles." They say the dough is made with just salt, water, and flour, aged for over two days, and freshly rolled out every day. With a phrase like "the slower it is, the better the flavor," you can tell this is a place that's serious about its noodles.

Inside Kosi Isu Branch: seating for solo diners and groups

Inside, the wood tones and soft lighting make Kosi Isu Branch comfortable and cozy even for solo dining. There's also seating for groups, so it works well for nearby office workers or gatherings too. Ordering is done via tablet at each table, which makes things easy.

Kosi Isu Branch menu and prices

* Don't forget — writing a Naver receipt review gets you a free canned drink :)

The menu has quite a range: cold udon, hot udon, kama udon, tonkatsu, and rice bowls. 👇 Here's the lineup:

• Bukkake udon ₩9,000
• Toriten bukkake udon ₩11,000
• Kitsune udon ₩11,000
• Ebi tempura udon ₩11,000
• Mazesoba udon ₩11,000
• Tonkatsu ₩11,500
• Cheese katsu ₩12,500
• Mixed katsu ₩14,500
• Beef bowl · Katsu bowl · Karaage bowl ₩10,500 each
• Sides – Inari sushi ₩2,000, shrimp tempura ₩2,000 (1pc), tempura set ₩5,000

The tonkatsu is famous too, but this time I went with two bowls of udon. (Something about that day just made me crave noodles.)

Tenbukkake ₩11,000, kitsune udon (hot) ₩11,000. Both came with inari sushi and cabbage salad on the side, making for a very filling spread. We're not exactly light eaters, but the portions were big enough that we were completely stuffed by the end.

Warm kitsune udon (udon with sweet fried tofu)

First, kitsune udon — think of it as fried tofu udon. Thick pieces of fried tofu sit on top, soaking up the broth so each bite is moist. The broth, made from anchovy, kelp, and bonito, is mild but deeply savory. Completely ideal when you're craving a warm bowl of soup udon to soothe your stomach.

Maybe because it's house-made, the noodles are on another level. Plump and springy, they get chewier the more you chew — the kind of texture that keeps pulling you back in (like Shrimp Crackers?). The noodles alone were tasty enough that I kept slurping them up before they went soft.

The main order: cold tenbukkake udon with tempura

And now the main event of the day — tenbukkake! Big shrimp and sweet pumpkin tempura sit on top of cold noodles, with grated radish, lemon, scallion, and seaweed on the side. You pour the special soy-based sauce over it and mix everything together. Cold noodles are especially fitting in summer, and the distinct aroma and seasoning of this tsuyu sauce were outstanding *_*

After pouring the soy sauce and lifting the noodles, the cold strands are springy and bouncy through and through. The seasoning isn't too strong, so the natural flavor of the house-made noodles really comes through. The inari sushi that came alongside was seasoned just right too — a solid fix for a carb-loving nation's cravings.

The tempura on top of the tenbukkake was genuinely, seriously crunchy, and packed inside. Shrimp tempura these days can honestly be disappointing a lot of the time, but the shrimp meat here was so plump it made me gasp — totally satisfying!! The batter is thin and not greasy, so there's no heaviness and I just kept picking pieces up. I wanted to eat it while it was still crispy, so I went straight for the tempura first, no hesitation ^^

Cold udon vs warm udon at Kosi Isu Branch: the verdict

I got to enjoy cold tenbukkake and warm kitsune udon together, two bowls with very different personalities. The house-made noodles were clearly a cut above, and the tempura and sides made it a satisfying meal overall. If you're craving udon or tonkatsu around Isu or Sadang, I'd recommend this as a light, easy option.

Hours, break time and parking at Kosi Isu Branch

Kosi Isu Branch is open 11:20–15:20 and 17:00–21:00, with last orders at 14:50 and 20:30. There's a break time in between. The building's underground parking lot is free for 1 hour.