# Seongsu Japanese restaurant lunch with tonkatsu and udon: Kosi

- By Hyeon (https://superchart.com/en/@queue-side-menu/)
- Written Sep 10, 2026
- Local places › Restaurants › Seongdong, Seoul
- Sponsored: This visit was sponsored by the business.
- English edition: https://superchart.com/en/@queue-side-menu/seongsu-kosi-katsu-udon-lunch/
- Also in: [한국어](https://superchart.com/ko/@queue-side-menu/seongsu-kosi-katsu-udon-lunch/index.md)

## In short

Kosi Seongsu Branch is a Japanese restaurant in Seongdong, Seoul, serving tonkatsu and udon set meals. My husband added udon to a half-and-half katsu set, while I added tonkatsu to a bukkake udon set and we shared a sweet potato cheese croquette. Verdict: a satisfying lunch when you both want different mains.

![Lunch menu at Kosi Seongsu Branch](https://img.superchart.com/images/seongsu-kosi-katsu-udon-lunch/seongsu-kosi-katsu-udon-lunch-01-1lrpj-1200.webp)

My husband and I headed out for lunch near home and visited Kosi Seongsu Branch. When we choose lunch, we often quietly end up craving different things, haha. That day too, he wanted tonkatsu more, while I was more in the mood for udon.

But Kosi has tonkatsu and udon set meals, with extra items you can add on, so we each chose what we wanted as our main. He ordered the half-and-half katsu set with extra udon, while I ordered the bukkake udon set with extra tonkatsu. We also got a sweet potato cheese croquette on the side.

Writing it out, we both ended up eating tonkatsu and udon anyway, haha.

![Visit to Kosi Seongsu Branch](https://img.superchart.com/images/seongsu-kosi-katsu-udon-lunch/seongsu-kosi-katsu-udon-lunch-02-i2x43-900.webp)

![Lunch at Kosi Seongsu Branch](https://img.superchart.com/images/seongsu-kosi-katsu-udon-lunch/seongsu-kosi-katsu-udon-lunch-03-1ecuz-900.webp)

![Interior and menu at Kosi Seongsu Branch](https://img.superchart.com/images/seongsu-kosi-katsu-udon-lunch/seongsu-kosi-katsu-udon-lunch-04-1ipxk-900.webp)

## Lunch near home at Kosi Seongsu Branch

Kosi Seongsu Branch is a Japanese restaurant centered around tonkatsu and udon. We visited at lunchtime, and the menu ranged from tonkatsu sets to udon, so it was easy for each of us to pick something to suit our taste.

Rather than ordering just one set meal, you can add tonkatsu or udon. On days when you want both, like we did, it makes for a nice combination.

![Tonkatsu and udon menu at Kosi Seongsu Branch](https://img.superchart.com/images/seongsu-kosi-katsu-udon-lunch/seongsu-kosi-katsu-udon-lunch-05-lbtzf-900.webp)

![Set meal selection at Kosi Seongsu Branch](https://img.superchart.com/images/seongsu-kosi-katsu-udon-lunch/seongsu-kosi-katsu-udon-lunch-06-1liys-900.webp)

When a place is near home, sometimes you just want a familiar meal like tonkatsu or udon rather than anything elaborate, right? That was exactly the kind of day it was for us!

![Tonkatsu and udon for lunch](https://img.superchart.com/images/seongsu-kosi-katsu-udon-lunch/seongsu-kosi-katsu-udon-lunch-07-1mcff-966.webp)

## My husband's half-and-half katsu set

![Half-and-half katsu set](https://img.superchart.com/images/seongsu-kosi-katsu-udon-lunch/seongsu-kosi-katsu-udon-lunch-08-1ref6-900.webp)

First up was my husband's half-and-half katsu set. Instead of just one kind of tonkatsu, it came with two kinds of katsu, so it was nice to alternate between them.

![Half-and-half katsu set with two kinds of katsu](https://img.superchart.com/images/seongsu-kosi-katsu-udon-lunch/seongsu-kosi-katsu-udon-lunch-09-1v5i7-900.webp)

I tried a piece or two from beside him, and freshly made tonkatsu really is best eaten right away while it's warm, haha. Being able to switch between two varieties rather than eating just one was another good thing about the half-and-half katsu.

![Half-and-half katsu set with extra udon](https://img.superchart.com/images/seongsu-kosi-katsu-udon-lunch/seongsu-kosi-katsu-udon-lunch-10-11pcu-900.webp)

He added udon to his meal too. The tonkatsu set alone would have been enough, but he said he wanted a warm broth alongside it, so he added it—and the table became quite a feast, haha.

## Bukkake udon set with extra tonkatsu

![Bukkake udon set with extra tonkatsu](https://img.superchart.com/images/seongsu-kosi-katsu-udon-lunch/seongsu-kosi-katsu-udon-lunch-11-1potm-900.webp)

I ordered the bukkake udon set that day. I was craving bukkake udon—udon tossed with a concentrated sauce—rather than hot broth udon. I wanted udon as my main but didn't want to give up tonkatsu either, so I added tonkatsu instead.

My husband added udon to tonkatsu, and I added tonkatsu to udon... Once we had ordered, I realized we had simply picked our meals in opposite ways, haha.

![Bukkake udon set](https://img.superchart.com/images/seongsu-kosi-katsu-udon-lunch/seongsu-kosi-katsu-udon-lunch-12-1seh7-900.webp)

![Bukkake udon served with tonkatsu](https://img.superchart.com/images/seongsu-kosi-katsu-udon-lunch/seongsu-kosi-katsu-udon-lunch-13-emzl2-900.webp)

For the bukkake udon, I mixed the noodles well with the toppings that came with it. It had a different feel from broth udon, and it paired nicely with bites of tonkatsu in between.

![Bukkake udon mixed with toppings](https://img.superchart.com/images/seongsu-kosi-katsu-udon-lunch/seongsu-kosi-katsu-udon-lunch-14-1syku-966.webp)

If it feels disappointing to choose only one between tonkatsu and udon, adding the one you want to a set meal like we did is a good option too.

## The sweet potato cheese croquette we couldn't pass up

After ordering two set meals and extras, we even got a side dish, haha. The sweet potato cheese croquette on the menu caught our eye, so we ordered that too.

![Sweet potato cheese croquette side dish](https://img.superchart.com/images/seongsu-kosi-katsu-udon-lunch/seongsu-kosi-katsu-udon-lunch-15-yj7l5-900.webp)

It was nice to share one here and there while eating the tonkatsu and udon. The sweet potato and cheese combination gave it a different feel from the mains, so I was glad we ordered a side too. One was just right for the two of us to share.

## After lunch at Kosi Seongsu Branch

Since my husband and I each ordered what we wanted, we ended up trying more variety than expected: a half-and-half katsu set with udon, a bukkake udon set with tonkatsu, and a sweet potato cheese croquette. I also liked that we could choose the menu we each wanted as our main, then add tonkatsu or udon to eat together.

![Lunch spread with tonkatsu and udon](https://img.superchart.com/images/seongsu-kosi-katsu-udon-lunch/seongsu-kosi-katsu-udon-lunch-16-90uy5-900.webp)

It was a nice place to stop by for lunch as a couple, or on a day when you want a meal of tonkatsu or udon near home. Above all, neither of us had to give up what we wanted—we ordered our preferred mains and thoroughly enjoyed the extras too, haha.

There are so many restaurants in the neighborhood that my husband and I tend to seek out new places rather than revisit ones we liked. But as we left Kosi, we both said, “Let's come back next time we're craving tonkatsu or udon.” Haha. Since we both said the same thing, I think we liked it quite a lot.

## Where it is

- Kosi Seongsu Branch (코시 성수점) (코시 성수점)
- 31 Sangwon 1-gil, Seongdong-gu, Seoul, South Korea
- 서울특별시 성동구 상원1길 31 1층
- 37.5464155, 127.0474867
- Google Maps: https://www.google.com/maps/search/%EC%BD%94%EC%8B%9C%20%EC%84%B1%EC%88%98%EC%A0%90/@37.5464155,127.0474867,17z

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Superchart · https://superchart.com/en/@queue-side-menu/seongsu-kosi-katsu-udon-lunch/ · https://superchart.com/llms.txt