# Isu Station Japanese dinner with sofa seats, full house: Kosi

- By Miro (https://superchart.com/en/@kitchen-door-table/)
- Written Sep 8, 2026
- Local places › Restaurants › Dongjak, Seoul
- Sponsored: This visit was sponsored by the business.
- English edition: https://superchart.com/en/@kitchen-door-table/kosi-isu-cheese-katsu-cold-udon/
- Also in: [한국어](https://superchart.com/ko/@kitchen-door-table/kosi-isu-cheese-katsu-cold-udon/index.md)

## In short

Kosi Isu Branch is a Japanese restaurant serving house-made udon and tonkatsu near Isu Station in Dongjak, Seoul. Visiting at 6:30pm without a reservation for two, the writer found the place fully packed but scored a sofa seat, ordering toriten bukkake udon for ₩11,000 and mixed tonkatsu for ₩13,500, with the chewy cold udon soaked in unsalted sauce the standout dish. If choosing just one menu item again, it would be the bukkake udon.

## Good to know

- **Location**: 300 Sadang-ro, 1F 126, 127, Dongjak-gu, Seoul (119m from Isu Station Exit 9, Lines 4 & 7)
- **Hours**: Daily 11:20 - 21:00
- **Break time**: 15:20 - 17:00 (last order 14:50, 20:30)
- **Parking**: 1 hour free in building basement lot
- **Reservations**: Only available for groups of 5 or more
- **Toriten Bukkake Udon**: ₩11,000
- **Mixed Tonkatsu**: ₩13,500
- **Seating**: Regular seats plus sofa seating available
- **Event**: Free drink can with Naver receipt review

*as written by the visitor on Sep 8, 2026*

My friend and I were trying to figure out what to eat near Isu Station when, in the last days of summer, I suddenly craved cold udon !!!

🤍 Cold udon + tonkatsu = love 🤍

The place was called Kosi. Here's my review ✔️

## Kosi Isu Branch: location and hours

- 🏠 300 Sadang-ro, 1F 126, 127, Dongjak-gu, Seoul, South Korea
- ✔️ 119m from Isu Station Exit 9 (Lines 4, 7)
- ⏰ Daily 11:20 - 21:00 (break time 15:20 - 17:00) (last order 14:50, 20:30)
- 🚙 Parking available (1 hour free in building basement lot)

![Exterior of Kosi Isu Branch near Isu Station Exit 9](https://img.superchart.com/images/kosi-isu-cheese-katsu-cold-udon/kosi-isu-cheese-katsu-cold-udon-01-pkaff-900.webp)

Kosi is right there when you come out of Isu Station Exit 9. Exit 9 is currently under construction, so we came out Exit 8 and crossed the street instead. Isu Station seems to have great restaurants clustered everywhere you look, haha,, it's nice that way.

![Entrance and surrounding street of Kosi Isu Branch](https://img.superchart.com/images/kosi-isu-cheese-katsu-cold-udon/kosi-isu-cheese-katsu-cold-udon-02-tb61v-900.webp)

![Interior of Kosi Isu Branch packed with customers](https://img.superchart.com/images/kosi-isu-cheese-katsu-cold-udon/kosi-isu-cheese-katsu-cold-udon-03-wmvss-900.webp)

![Dining area at Kosi Isu Branch with sofa seating](https://img.superchart.com/images/kosi-isu-cheese-katsu-cold-udon/kosi-isu-cheese-katsu-cold-udon-04-1uur1-900.webp)

## Showing up at 6:30pm without a reservation — was there a table?

Reservations are only possible for groups of 5 or more, so as a party of two we went without one. Kosi at around 6:30 was already completely full,, whoa. The place was packed with people. The rightmost photo was taken on our way out — besides the regular seating there were also sofa seats like this, which was great. Lucky enough to get a sofa seat !!!!! >_< (so comfy)

![Order screen set to Japanese language mode](https://img.superchart.com/images/kosi-isu-cheese-katsu-cold-udon/kosi-isu-cheese-katsu-cold-udon-05-us45l-900.webp)

When I went to order, I noticed the screen was set to Japanese. Must be a genuine Japanese restaurant that real Japanese customers visit too. Took a shot with my heart racing a little.

The menu had a wide range — udon, tonkatsu, katsu hot pot and more. * Don't miss the Naver receipt review event, which gets you a free can of a drink !!! *

![Kosi menu featuring udon, tonkatsu and katsu hot pot](https://img.superchart.com/images/kosi-isu-cheese-katsu-cold-udon/kosi-isu-cheese-katsu-cold-udon-06-emxtg-900.webp)

## Toriten Bukkake Udon (₩11,000)

The dish that caught my eye first was this bukkake udon! Kosi's dough apparently goes through a first and second fermentation before being finished after 48 hours (new to me).

![A bowl of toriten bukkake udon](https://img.superchart.com/images/kosi-isu-cheese-katsu-cold-udon/kosi-isu-cheese-katsu-cold-udon-07-1dxm5-900.webp)

Smooth udon noodles topped with chopped scallions and seaweed flakes.

![Udon noodles topped with scallions and seaweed flakes](https://img.superchart.com/images/kosi-isu-cheese-katsu-cold-udon/kosi-isu-cheese-katsu-cold-udon-08-slmc2-900.webp)

And on one side comes the toriten (fried chicken). Cold udon with fried chicken,, already exactly my style.

![Toriten fried chicken served alongside the udon](https://img.superchart.com/images/kosi-isu-cheese-katsu-cold-udon/kosi-isu-cheese-katsu-cold-udon-09-1t5cp-900.webp)

![Close-up of the toriten fried chicken](https://img.superchart.com/images/kosi-isu-cheese-katsu-cold-udon/kosi-isu-cheese-katsu-cold-udon-10-5mff2-900.webp)

And a cute piece of fried tofu pouch plus the special soy-based sauce!

![A piece of fried tofu pouch and special soy sauce](https://img.superchart.com/images/kosi-isu-cheese-katsu-cold-udon/kosi-isu-cheese-katsu-cold-udon-11-mb9ht-900.webp)

## Mixed Tonkatsu (₩13,500)

Classic is best, so I also ordered tonkatsu. Wanting both cheese katsu and pork loin katsu but can't decide? Best menu item for that exact dilemma.

![Mixed tonkatsu with both cheese katsu and pork loin katsu](https://img.superchart.com/images/kosi-isu-cheese-katsu-cold-udon/kosi-isu-cheese-katsu-cold-udon-12-7pqjv-900.webp)

![Cross-section of a large tonkatsu piece](https://img.superchart.com/images/kosi-isu-cheese-katsu-cold-udon/kosi-isu-cheese-katsu-cold-udon-13-17tb8-900.webp)

Each piece came out as one big chunk — the portion was genuinely huge !!!

![Full spread of bukkake udon and mixed tonkatsu](https://img.superchart.com/images/kosi-isu-cheese-katsu-cold-udon/kosi-isu-cheese-katsu-cold-udon-14-qllx3-900.webp)

## Bukkake udon with sauce poured in — how did it taste?

And so the full spread was complete 🤍

Bukkake udon is eaten by pouring the accompanying sauce over the noodles and mixing it in. The sauce wasn't salty at all, so it was fine to pour all of it in. I liked being able to eat it nice and soupy, haha.

![Bukkake udon mixed soupy with poured sauce](https://img.superchart.com/images/kosi-isu-cheese-katsu-cold-udon/kosi-isu-cheese-katsu-cold-udon-15-61wgd-1200.webp)

Insanely (?) chewy noodles and fried chicken soaked full of sauce,, why did I only just discover this now.

The chicken's fried coating was crispy yet soaked with the sauce so it went soft and salty… just delicious, and the udon was seriously chewy. The 48-hour aging really seems to be legit !!!! 🔥

![A piece of cheese katsu with stretchy cheese](https://img.superchart.com/images/kosi-isu-cheese-katsu-cold-udon/kosi-isu-cheese-katsu-cold-udon-16-102ne-900.webp)

## A bite each of cheese katsu and pork loin katsu

For the tonkatsu, I went for cheese first. The cheese, meat and breading are almost a perfect 1:1:1 ratio, so no part of it is lacking. Personally I don't love it when the breading is too thin, and Kosi's katsu breading was just the right thickness and delicious 🤤

![A bite of crispy-breaded pork loin katsu](https://img.superchart.com/images/kosi-isu-cheese-katsu-cold-udon/kosi-isu-cheese-katsu-cold-udon-17-akg8c-900.webp)

A bite of the regular katsu too, wow — overall, as you'd expect from a solid Japanese restaurant, they really know how to fry. The crispiness held up well even after time passed !!!

![A piece of toriten fried chicken dipped in sauce](https://img.superchart.com/images/kosi-isu-cheese-katsu-cold-udon/kosi-isu-cheese-katsu-cold-udon-18-149n6-900.webp)

And here it is, the real star (?), the fried chicken. So good,, if I could only eat one menu item next time, I'd go with the bukkake udon ✌🏻✨

## Why I'd recommend this as an Isu Station Japanese restaurant

I recommend Kosi to anyone looking for good food near Isu Station. The interior is clean and the food is great, so it seems like a nice spot for a date too, and I saw a lot of friends and families dining there! If you're after a good Japanese restaurant, I'd recommend this one, haha. Today's challenge, the bukkake udon — success~! 🤓

## Where it is

- Kosi Isu Branch (코시 이수점)
- 300 Sadang-ro, 1F 126, 127, Dongjak-gu, Seoul, South Korea
- 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/@kitchen-door-table/kosi-isu-cheese-katsu-cold-udon/ · https://superchart.com/llms.txt