# Dongjak Japanese restaurant for mixed tonkatsu: Kosi Isu Branch

- By Yeobaek (https://superchart.com/en/@folded-napkin/)
- Written Sep 10, 2026
- Local places › Restaurants › Dongjak, Seoul
- Sponsored: This post was written with support for a visit to the restaurant.
- English edition: https://superchart.com/en/@folded-napkin/isu-tempura-udon-koshi/
- Also in: [한국어](https://superchart.com/ko/@folded-napkin/isu-tempura-udon-koshi/index.md)

## In short

Kosi Isu Branch is a Japanese restaurant in Dongjak, Seoul, near Exit 9 of Isu Station. I ordered ten bukkake udon, mixed tonkatsu, and king shrimp katsu for chewy cold noodles and crisp cutlets. A satisfying choice when you want cold udon and tonkatsu together.

## Good to know

- **Location**: On the first floor of Isu Xi, near Exit 9 of Isu Station
- **Parking**: Building underground parking available; 1 hour of free parking support

*as written by the visitor on Sep 10, 2026*

![Cold udon and tonkatsu at Kosi Isu Branch](https://img.superchart.com/images/isu-tempura-udon-koshi/isu-tempura-udon-koshi-01-57u3i-966.webp)

## Kosi Isu Branch near Exit 9 of Isu Station

![Introduction to visiting Kosi Isu Branch](https://img.superchart.com/images/isu-tempura-udon-koshi/isu-tempura-udon-koshi-02-xhtth-720.webp)

I spent ages wondering what to have for dinner near Isu Station. It was still hot out, and all of a sudden I was craving refreshing cold udon rather than a steaming bowl of soup. But udon alone felt a little lacking, so this time I went somewhere that also serves tonkatsu (Japanese pork cutlet), haha.

That place was Kosi Isu Branch. It is close to Exit 9 of Isu Station, so it was easy to find, and I loved the menu right away because I could have handmade udon and tonkatsu together.

## Location and the menu outside

![Exterior of Kosi Isu Branch on the first floor of Isu Xi](https://img.superchart.com/images/isu-tempura-udon-koshi/isu-tempura-udon-koshi-03-188ou-966.webp)

Kosi Isu Branch is on the first floor of the Isu Xi building. It is just a short walk from Exit 9 of Isu Station, so getting there by public transit was pretty convenient. You can also use the building's underground parking, with one hour of free parking support. Worth noting if you are driving.

![Menu information in front of Kosi Isu Branch](https://img.superchart.com/images/isu-tempura-udon-koshi/isu-tempura-udon-koshi-04-1ifno-966.webp)

The menu and prices were displayed in front of the restaurant, so it was nice to look over what to order before going in.

## A comfortable interior for solo dining, too

![Clean interior of Kosi Isu Branch](https://img.superchart.com/images/isu-tempura-udon-koshi/isu-tempura-udon-koshi-05-w0sez-966.webp)

Inside, the overall atmosphere was clean and tidy.

![Solo dining seats at Kosi Isu Branch](https://img.superchart.com/images/isu-tempura-udon-koshi/isu-tempura-udon-koshi-06-ldaqe-966.webp)

It is not a huge restaurant, but there are seats for eating alone, so it looked easy enough to come by yourself.

![Tablet ordering system at the table](https://img.superchart.com/images/isu-tempura-udon-koshi/isu-tempura-udon-koshi-07-1ffa9-966.webp)

In particular, each table has a tablet for ordering, so you can take your time choosing without having to call over a staff member,

![Tablet ordering and payment screen](https://img.superchart.com/images/isu-tempura-udon-koshi/isu-tempura-udon-koshi-08-1sc6g-966.webp)

then order and pay all at once. I find this kind of setup quietly convenient these days, haha.

## Ordering ten bukkake udon and mixed tonkatsu

You could say udon and tonkatsu are Kosi's signature dishes. From handmade udon to a range of tonkatsu options, the menu lets you choose according to your taste.

There were so many kinds of tonkatsu that I debated what to get, then ordered the mixed tonkatsu so I could enjoy two varieties at once. And the dish I most wanted to try that day! Of course, ten bukkake udon too, haha. I even added king shrimp katsu as a side! I wanted to try everything one by one, but when the food arrived, I thought I had done well ordering it this way, lol.

## Ten bukkake udon noodles and tsuyu

![Ten bukkake udon at Kosi Isu Branch](https://img.superchart.com/images/isu-tempura-udon-koshi/isu-tempura-udon-koshi-09-12mxl-966.webp)

The dish I was most looking forward to that day was the ten bukkake udon. On hot days, instead of hot udon,

![Refreshing cold udon](https://img.superchart.com/images/isu-tempura-udon-koshi/isu-tempura-udon-koshi-10-nsy8y-966.webp)

I find myself more drawn to cold udon that is refreshing and clean-tasting.

Maybe because the noodles were made in-house, they had quite a chewy bite.

![Handmade udon noodles](https://img.superchart.com/images/isu-tempura-udon-koshi/isu-tempura-udon-koshi-11-k2ezj-966.webp)

Eating the chilled udon noodles with tsuyu (Japanese dipping sauce), I could really feel that springy texture.

![Udon noodles eaten with tsuyu](https://img.superchart.com/images/isu-tempura-udon-koshi/isu-tempura-udon-koshi-12-1aab6-966.webp)

The noodles especially had not gone soft and still had plenty of bounce, so I loved how pleasantly chewy they became with every bite, haha.

![Ten bukkake udon topped with tempura](https://img.superchart.com/images/isu-tempura-udon-koshi/isu-tempura-udon-koshi-13-zvju0-966.webp)

True to ten bukkake udon, it came topped with crisp tempura, so the savory fried flavor alongside the cold udon made it feel more substantial than simple cold udon. The tsuyu was salty and full of umami, and it seasoned the chewy noodles really well.

![Cold udon served with tempura](https://img.superchart.com/images/isu-tempura-udon-koshi/isu-tempura-udon-koshi-14-sdzdt-966.webp)

Above all, it was cold and refreshing, just right for a hot day. Having bites of tempura in between added a crisp texture, and I enjoyed it all the way through, haha.

## Mixed tonkatsu with salt and wasabi

Next up was the mixed tonkatsu I ordered!

![Mixed tonkatsu at Kosi Isu Branch](https://img.superchart.com/images/isu-tempura-udon-koshi/isu-tempura-udon-koshi-15-wmffk-966.webp)

Rather than eating just one kind of tonkatsu, I wanted to try two flavors together, so I ordered the mixed plate—and it was quietly a great choice. The breading was crisp overall, and the meat was thick, making even one piece feel pretty filling.

Since it came as a mixed plate, it was fun comparing the two varieties, and it was easy to keep eating without getting tired of it. The combination of crisp breading and tender meat was good, and I could really taste that characteristic savory richness of tonkatsu.

![Tonkatsu served with salt and wasabi](https://img.superchart.com/images/isu-tempura-udon-koshi/isu-tempura-udon-koshi-16-1e57p-966.webp)

It was tasty dipped in the standard tonkatsu sauce, but personally, I also recommend salt with wasabi! A little salt and a bit of wasabi on a piece of tonkatsu seemed to bring out its savory flavor even more, haha. Add a little pepper too, and it cuts through the richness, so several pieces do not feel too heavy. And with the mixed plate, it was more fun because I could alternate between the two flavors depending on what I felt like eating.

## Udon and tonkatsu together on a hot day

After eating at Kosi Isu Branch, the ten bukkake udon I had been looking forward to was my personal favorite. The chewy, springy handmade udon noodles with cool tsuyu and crisp tempura made for the kind of clean, refreshing meal I crave on a hot day.

Having the mixed tonkatsu alongside it made the meal much more filling than having just one dish. I also personally loved being able to enjoy two tonkatsu varieties at once by ordering the mixed plate, haha. If, like me, you want udon and tonkatsu, do not give one up—just order both, lol. Especially in hot weather like this, cold ten bukkake udon and crisp tonkatsu turned out to be such a good pairing.

## Where it is

- Kosi Isu Branch (코시 이수점)
- 126–127, 1F, 300 Sadang-ro, Dongjak-gu, Seoul, South Korea (서울특별시 동작구 사당로 300 1층 126호, 127호)
- 서울특별시 동작구 사당로 300 1층 126호, 127호
- 37.4844642, 126.9808303
- Google Maps: https://www.google.com/maps/search/%EC%BD%94%EC%8B%9C%20%EC%9D%B4%EC%88%98%EC%A0%90/@37.4844642,126.9808303,17z

---

Superchart · https://superchart.com/en/@folded-napkin/isu-tempura-udon-koshi/ · https://superchart.com/llms.txt