Ttukseom Station udon restaurant: cold udon + ₩5,000 katsu side, Kosi

Let me tell you about my visit to Kosi Seongsu Branch, a tonkatsu spot near Ttukseom Station where you get springy, lively udon and crispy katsu in one meal.

Kosi Seongsu Branch opening hours and parking

Do check the opening hours before you go (checking ahead is a must!). It's also worth looking over the amenities info in advance.

The restaurant has no dedicated parking of its own. The alleys around Seongsu and Ttukseom Station are a maze, so I'd suggest taking public transport or using a nearby paid public parking lot! (Please double-check the parking situation before you go, haha.)

Where is Kosi Seongsu Branch? How far from Ttukseom Station?

Kosi Seongsu Branch is about a 3–5 minute walk from Exit 5 of Ttukseom Station on Subway Line 2, so it's really easy to get to. It's also within walking distance of Seongsu Station, which makes this tonkatsu spot a perfect stop on a Seongsu outing.

Kosi Seongsu Branch menu and prices

Basic udon runs about ₩9,000–₩11,000, and tonkatsu sets (jeongsik, set meals) are in the ₩11,500–₩15,000 range. There's a good variety of house-made udon and katsu dishes, from hot-broth udon to chilled bukkake (cold udon with concentrated sauce) and tonkatsu sets.

The side options are well done too: you can add katsu or tempura separately. I had the cold bukkake udon for ₩9,000, and added a tonkatsu side (₩5,000) at a very reasonable price for a hearty meal.

There's a review coupon on Naver, so be sure to use it~~~!!

Cold udon with a tonkatsu side: how did it taste?

I had Kosi's chilled udon with a tonkatsu side added, and it was an amazing combination! Maybe because the noodles are made in-house, the cold udon had an exceptionally chewy, springy bite.

The tsuyu (Japanese noodle sauce) wasn't salty and had deep savory flavor. The tonkatsu I ordered as a side was textbook "crispy outside, juicy inside" (geotbasokchok), the kind of quality you'd expect from a top tonkatsu place near Ttukseom Station.

Kosi Seongsu Branch atmosphere and seating

The interior feels clean and tidy, with comfortably spaced tables for a relaxed meal. There's also a bar counter that's great for dining alone, so it's easy to drop in by yourself.

Overall it has that cozy yet stylish feel of a Japanese restaurant. With soft lighting and a clean white-and-wood interior, it works well for a date or a get-together with friends.

What I liked

As a house-made noodle specialist, Kosi's noodle texture is outstanding, and that was my favorite part. Udon alone can feel slightly lacking, so I really liked that you can add a high-quality tonkatsu as a side at a reasonable price.

What I didn't like: peak-time waits

It's a well-known place, so there can be a bit of a wait on weekends and at weekday lunch peak times, which was a small downside. Table turnover is fairly quick though, so it's well worth the wait.

Who I recommend it to

• Anyone who wants properly made, chewy Japanese-style udon
• Anyone who wants noodles and katsu in the same meal
• Anyone looking for a clean, reliable place to eat near Seongsu or Ttukseom

Overall verdict

The springy cold udon was really, really... delicious, and the tonkatsu went with it perfectly. Kosi Seongsu Branch offers a thoughtfully made meal in a clean setting, and I'd definitely come back whenever I'm craving cold udon again!