Solo-dining tonkatsu restaurant in Seongsu-dong: Kosi Seongsu Branch

I was looking for somewhere to eat lunch alone in Seongsu and ended up at Kosi Seongsu Branch! I was really craving tonkatsu that day, and while searching I found they had a half-and-half katsu where you can get both loin katsu and cheese katsu, so I decided on this place right away haha.

Where is Kosi Seongsu Branch, and what are its hours?

Kosi Seongsu Branch is at 31 Sangwon 1-gil, 1st floor, Seongdong-gu, Seoul, near Ttukseom Station. Hours are 11:00 - 21:00 with a break time of 15:00 - 17:00, and last order is 20:30.

• 📍 31 Sangwon 1-gil, 1st floor, Seongdong-gu, Seoul
• ⏰ 11:00 - 21:00
• ⏰ Break time 15:00 - 17:00
• ⏰ Last order 20:30
• ✔️ Near Ttukseom Station
• ✔️ Bar seating good for solo dining

Weekday lunch wait: what time does Kosi Seongsu Branch quiet down?

I visited on a weekday afternoon, and there were more people than I expected, so there was a wait. Lunchtime definitely seems to get crowded. Still, by around 1:30pm when I was there, it started thinning out a bit haha. If you want to avoid the wait, visiting a little outside the lunch peak might be a good idea!

I also came alone that day and it was genuinely comfortable for solo dining!! There's a nice window-side seat for eating alone, so it wasn't awkward at all coming to eat tonkatsu by myself. Finding a solo dining spot in Seongsu can sometimes be tricky, but this place was easy and comfortable to eat at alone haha.

Ordering the fresh pork loin half-and-half katsu: what comes on the plate

What I ordered was the fresh pork loin half-and-half katsu! Loin katsu and cheese katsu come together, perfect for when it's a shame to pick just one. There was a good range of tonkatsu dishes, and plenty of udon and rice bowls too!

I was torn between cheese katsu and loin katsu, but luckily there was a half-and-half menu with both cheese and loin in it, so that's what I picked! It wasn't even that expensive for Seongsu prices haha. Really good.

How is the loin katsu cooked, and how is the breading?

First off, the doneness of the tonkatsu was really to my liking.

It wasn't overcooked and dry, nor undercooked in a worrying way inside — it was just right! The breading was crispy while the meat inside was moist, so eating them together was delicious. The loin was plenty tasty, but for me the cheese tonkatsu was really the star here lol.

Cheese katsu: how much cheese actually oozes out?

When you cut into it, the cheese inside oozes out and this is seriously... if you like cheese, you have to try this haha. It's not just a little bit of cheese in there — it's generously packed, so you really get that savory, soft flavor.

The tonkatsu was crispy on the outside with warm cheese flowing out inside, and the combination was so good together! Eating only cheese katsu might get a little rich after a while, but ordering the half-and-half meant I could alternate with the loin, which was actually great. Eating one loin bite then one cheese bite, it disappeared fast lol.

First visit to Kosi Seongsu Branch? Get the half-and-half katsu

I originally just came because I wanted tonkatsu, but it turned out way more delicious than I expected. If it's your first visit, I'd personally recommend the half-and-half katsu! It's great because you get to try both loin and cheese, and for me the cheese katsu was totally my thing. It had so much cheese packed in that it oozed out, which made it look great and taste savory — it was the most memorable part haha.

Overall, the tonkatsu doneness was just right and the breading was crispy, so it was a delicious meal. It was also nice that I could eat comfortably even alone. That said, there was a wait even on the weekday afternoon I visited, so if you go during lunch hours you might have to wait a bit. Based on the day I went, things seemed to ease up a little after 1:30pm!

If you're looking for a good tonkatsu spot in Seongsu or a place to eat alone near Ttukseom, Kosi Seongsu Branch was solid :) Especially if you like cheese tonkatsu, I'd recommend the half-and-half katsu! The loin was tasty too, but the cheese katsu with cheese oozing out was seriously so good that I'd probably order it again next time haha.