Isu Station tonkatsu with kake udon add-on, packed to go: Kosi

In short

Kosi Isu Branch is a handmade udon and tonkatsu restaurant about 200m from Exit 9 of Isu Station in Dongjak, Seoul. Visiting on a weekday evening, the writer ordered tonkatsu with kake udon added, plus toriten bukkake udon with extra tonkatsu — so much food that the leftover tonkatsu had to be packed to go. A great spot to try both hot and cold udon in one sitting by pairing a single dish with a side.

Pepper, sesame, and spicy powder containers on the table

Good to know

Hours
Daily 11:20–21:00
Break time
15:20–17:00
Last order
14:50, 20:30
Location
1F, 126 & 127, 300 Sadang-ro, Dongjak-gu, Seoul, South Korea (about 200m from Isu Station Exit 9)
Tonkatsu
₩11,500
Kake udon add-on
₩3,500
Toriten bukkake udon
₩11,000
Extra tonkatsu
₩5,000
Pepsi Zero
₩2,000
Review event
One free canned drink for a Naver photo receipt review

as written by the visitor on Sep 6, 2026

A handmade udon spot near Isu Station: Kosi Isu Branch

Today I want to introduce a handmade udon restaurant near Isu Station — Kosi Isu Branch. It's the udon place that even appeared on 'Life's Masters' as the 'noodle-rolling master'! Kosi Isu Branch is about 200m from Isu Station Exit 9.

Exterior of Kosi Isu Branch near Isu Station
View around the entrance of Kosi Isu Branch

Cold udon and hot udon are the main menu items, and the tonkatsu (breaded pork cutlet) is famous too!

Kosi Isu Branch menu listing cold udon, hot udon, and tonkatsu
Udon menu board at Kosi Isu Branch

Weekday evening atmosphere

I visited on a weekday evening and the place was packed with customers. Must be a local favorite in Isu-dong, haha. Looked like a lot of families were visiting too.

Kosi Isu Branch dining hall packed with customers on a weekday evening
Table seating inside Kosi Isu Branch
Interior view of Kosi Isu Branch
Seating and aisle area at Kosi Isu Branch
Interior decor of Kosi Isu Branch
A seating area on one side of Kosi Isu Branch
Interior and ordering area of Kosi Isu Branch

Menu lineup and my order

Besides udon, there are also rice dishes like gyudon (beef rice bowl), katsudon (pork cutlet rice bowl), and karaage-don (fried chicken rice bowl)!

Rice menu board with gyudon, katsudon, and karaage-don
Notice for the Naver receipt review event

There's also a Naver receipt review event going on — if you participate with a photo receipt review, you get one canned drink as a free service. Here's what I ordered~~~

  • Tonkatsu (₩11,500) + kake udon (₩3,500)
  • Toriten bukkake udon (₩11,000) + extra tonkatsu (₩5,000)
  • Pepsi Zero (₩2,000)

You can add side dishes to a single dish, so you can eat a variety of things and get a hearty meal. Adding tonkatsu on top of udon meant the portion was really huge ^^,,, In the end I couldn't finish the tonkatsu, so I asked to pack it to go, haha.

Ordered udon and tonkatsu set combination

There's also pepper, sesame, and spicy powder on the table~!

Pepper, sesame, and spicy powder containers on the table

The food comes out pretty fast! All the dishes I ordered arrived.

A table full of udon and tonkatsu dishes

What happens when you add kake udon to tonkatsu?

Tonkatsu (₩11,500) + kake udon (₩3,500) — I added kake udon to the tonkatsu single dish. I couldn't leave without trying the hot udon too, haha.

Tonkatsu single dish with kake udon added
Thick tonkatsu with cabbage salad side dish

Cabbage salad, tonkatsu sauce, salt, and wasabi come as basic side dishes. You can also ask for more if you run out.

The tonkatsu is really thick and dense right off the bat. Even eating just the tonkatsu alone was filling.

They mix ground sesame into the tonkatsu sauce too, adding a nutty aroma. Let me dip it in the sauce~~ There's salt too, but I love the combo of wasabi on top of the katsu sauce the most, haha.

The broth is really clean and deep, so it seems good even for kids to eat. Or it would also be great as a hangover cure, haha.

A piece of tonkatsu dipped in tonkatsu sauce

I wanted it a bit spicier so I added a little spicy powder~ The amount of udon wasn't too little either, just right. I definitely recommend trying different things with the set menu.

Kake udon broth with spicy powder added

The hot udon is exactly the clean kind of udon. It's brewed in the traditional Sanuki style and flavored with a secret soy sauce, making a light broth udon~ The noodles are so chewy they went down easily. The hot udon pairs especially well with kkakdugi (cubed radish kimchi)~

Chewy noodles in hot kake udon

Toriten bukkake udon + extra tonkatsu

Next up: toriten bukkake udon (₩11,000) + extra tonkatsu (₩5,000). The bukkake udon at Kosi Isu Branch is really famous too. It's one of the dishes that really suits summer. Since the extra tonkatsu was only ₩5,000, I ordered it, haha. The bukkake udon portion, though, is really huge~!

A large bowl of toriten bukkake udon
Bukkake udon served with one piece of inari sushi

Cabbage salad and one piece of inari sushi (fried tofu rice) also come with it~~~

Don't you ever want to try just the noodles alone once...? I wanted to slurp the noodles by themselves without the tsuyu (dipping sauce), lol.

They pour on the cold tsuyu~~ They squeezed in some lemon for a refreshing touch too. Since it's cold udon, the noodles feel even chewier and springier.

Toriten karaage soaked in tsuyu sauce

The karaage was so soft and paired well with the bukkake udon. Crispy karaage is great, but karaage lightly soaked in the tsuyu is also so delicious~~!!!!! This is the kind of toriten bukkake udon you'll crave again when it's hot out~~

The extra tonkatsu portion was really huge too! I couldn't finish the tonkatsu and packed it to go, haha. How about you all try the udon and tonkatsu at Kosi Isu Branch too~~???

Where it is

Kosi Isu Branch코시 이수점

1F, 126 & 127, 300 Sadang-ro, Dongjak-gu, Seoul, South Korea서울특별시 동작구 사당로 300 1층 126호, 127호

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