# Seongsu tonkatsu restaurant with zaru soba set and karaage don: Kosi - By Sohyun Bae (https://superchart.com/en/@mullae-quiet-plate/) - Written Sep 22, 2026 - Local places › Restaurants › Seongdong, Seoul - Sponsored: This post was written after being sponsored for a store visit. - English edition: https://superchart.com/en/@mullae-quiet-plate/seongsu-kosi-zaru-soba-karaage-don/ - Also in: [한국어](https://superchart.com/ko/@mullae-quiet-plate/seongsu-kosi-zaru-soba-karaage-don/index.md) ## In short Kosi Seongsu Branch is a tonkatsu and Sanuki udon restaurant one minute from Ttukseom Station Exit 6 in Seongdong, Seoul. The order here was the mixed katsu set with kake udon (14,500 won), the zaru soba set with tonkatsu (11,000 won) and a karaage don (10,500 won), built around crisp-outside, juicy-inside fresh pork loin katsu and chewy udon noodles. Kosi Seongsu Branch delivers the kind of value that makes it a candidate for the best tonkatsu meal you'll have in Seoul. ## Good to know - **Location**: 100m (about 1 min) from Ttukseom Station Exit 6; under 5 min from Seoul Forest Station Exit 1 - **Hours**: Mon-Sun 11:00-21:00 (last order 20:30), break 15:00-17:00 - **Parking**: 2 spaces in front of the restaurant, free for 1 hour; when full, paid public lots at Seongsu Culture & Welfare Center or Seongdong District Sports Center - **Mixed katsu (+3,500 won for the kake udon set)**: 14,500 won - **Zaru soba (+5,000 won for the tonkatsu set)**: 11,000 won - **Karaage don**: 10,500 won - **Ordering**: Kiosk at each table - **Seating**: Solo seats, group tables, open kitchen - **Price reference**: ₩10,500 ≈ $7.6 (2026-09-22) *as written by the visitor on Sep 22, 2026* ![Tonkatsu and udon spread at Kosi Seongsu Branch](https://img.superchart.com/images/seongsu-kosi-zaru-soba-karaage-don/seongsu-kosi-zaru-soba-karaage-don-01-itc0t-1200.webp) Hi, I'm Ddoromi :) Today I'm introducing an incredible value-for-money Japanese restaurant in Seongsu — perfect for solo dining, lunch, or a date! 🤤 It's a Seongsu tonkatsu spot that actor Kim Seung-soo raved about, and it's also been featured on SBS's Life's Grand Masters. To cut to the conclusion first: this was the best tonkatsu I've ever had, hands down, and every single dish I ordered was so satisfying that I just had to share it .. ´͈ ᵕ `͈ It's the Seongsu tonkatsu restaurant "Kosi" — Seongsu Branch! ## How to find Kosi Seongsu Branch, and is there a wait? Kosi Seongsu Branch is within 100m (about a 1-minute walk) from Ttukseom Station Exit 6, and about 5 minutes from Seoul Forest Station Exit 1, so it's really easy to find and get to. As a well-known Seongsu tonkatsu spot, there's even a waiting list sign-up station set up outside the store. ![Exterior of Kosi Seongsu Branch near Ttukseom Station](https://img.superchart.com/images/seongsu-kosi-zaru-soba-karaage-don/seongsu-kosi-zaru-soba-karaage-don-02-ti0sa-900.webp) ![Entrance sign of Kosi Seongsu Branch](https://img.superchart.com/images/seongsu-kosi-zaru-soba-karaage-don/seongsu-kosi-zaru-soba-karaage-don-03-1tcaa-m-900.webp) ![Waiting list sign-up station outside the restaurant](https://img.superchart.com/images/seongsu-kosi-zaru-soba-karaage-don/seongsu-kosi-zaru-soba-karaage-don-04-6c2iu-900.webp) ![Street view in front of the building housing Kosi Seongsu Branch](https://img.superchart.com/images/seongsu-kosi-zaru-soba-karaage-don/seongsu-kosi-zaru-soba-karaage-don-05-1s513-900.webp) Every time I've passed by there's been a wait, but this time the timing worked out and I got in lucky, with no wait at all ,,☘️ The turnover is fast, so don't worry too much about it - ( ̳• ·̫ • ̳) I got curious about what "Kosi" means, and apparently in Japan it describes a satisfying chewiness in food! ## Inside Kosi Seongsu Branch: solo seats, group tables and an open kitchen The interior of Kosi Seongsu Branch is bright, clean and comfortable overall, with both solo-dining seats and group seats, so it looked great for a date, solo lunch, or eating with a group! ![Bright, clean interior of Kosi Seongsu Branch](https://img.superchart.com/images/seongsu-kosi-zaru-soba-karaage-don/seongsu-kosi-zaru-soba-karaage-don-06-ir3rp-900.webp) ![Solo seating for solo diners](https://img.superchart.com/images/seongsu-kosi-zaru-soba-karaage-don/seongsu-kosi-zaru-soba-karaage-don-07-195qw-900.webp) ![Group seating for larger parties](https://img.superchart.com/images/seongsu-kosi-zaru-soba-karaage-don/seongsu-kosi-zaru-soba-karaage-don-08-8n0nj-900.webp) ![Open kitchen where cooking is visible](https://img.superchart.com/images/seongsu-kosi-zaru-soba-karaage-don/seongsu-kosi-zaru-soba-karaage-don-09-y6cde-900.webp) It's also an open kitchen, so you can see for yourself how cleanly the kitchen is kept, and watching the cooking happen right in front of you made me trust the place even more. ![Kiosk order machine at each table](https://img.superchart.com/images/seongsu-kosi-zaru-soba-karaage-don/seongsu-kosi-zaru-soba-karaage-don-10-19t3i-900.webp) ## What we ordered at Kosi Seongsu Branch and what it cost You can conveniently order via kiosk at each table. Here's what we ordered. - Mixed katsu (+ set upgrade to kake udon ₩3,500) ₩14,500 - Zaru soba (+ set upgrade to tonkatsu ₩5,000) ₩11,000 Since it's a great-value Japanese restaurant, the price for upgrading to a full set was also very reasonable! ## Kosi Seongsu Branch hours and parking - Hours: (Mon-Sun) 11:00 - 21:00 (last order 20:30), break time 15:00 - 17:00 - Parking: available / 2 spots in front of store, free for 1 hour - If full, use nearby public parking lots (paid) — Seongsu Culture & Welfare Center / Seongdong District Sports Center public lots ![Hours and parking information for Kosi Seongsu Branch](https://img.superchart.com/images/seongsu-kosi-zaru-soba-karaage-don/seongsu-kosi-zaru-soba-karaage-don-11-7x7n8-900.webp) There's also a Naver coupon, so make sure to grab that - ✨ ![Coupon information usable at the restaurant](https://img.superchart.com/images/seongsu-kosi-zaru-soba-karaage-don/seongsu-kosi-zaru-soba-karaage-don-12-xqaof-900.webp) ## Mixed katsu set: tonkatsu, king shrimp katsu, udon and salad First up is the mixed katsu set 🦐 It comes with tonkatsu, king shrimp katsu, udon, and salad all together. Such an insanely good-value, filling combo, right? 😳 Kosi, the Seongsu tonkatsu spot, uses domestic fresh pork loin that's pounded fresh every day, and it's fried as soon as it's ordered. I took a bite and honestly.. this was the best Japanese tonkatsu I've ever had.. (my partner agreed too). The breading was genuinely crispy and the inside was so, so tender — perfectly crispy-outside-tender-inside, and I just kept eating more... You seriously have to try this .. please do .. (for real) ![Mixed katsu set with tonkatsu and king shrimp katsu](https://img.superchart.com/images/seongsu-kosi-zaru-soba-karaage-don/seongsu-kosi-zaru-soba-karaage-don-13-m0o3q-900.webp) ### The Sanuki udon that comes with the set is the real surprise The king shrimp was really big and plump, and doesn't the crispiness of the batter come through just from the photo..?🥹 And the udon that came with it was also insane.. I regretted not ordering udon on its own too ... A lot of other tables were ordering udon as a standalone dish. Kosi's tonkatsu is amazing, but the udon is actually what's really famous — they say it's simmered in soy sauce imported directly from Japan, and they only use fresh noodles made with the 800-year-old traditional Sanuki method, using anchovies and kelp sourced directly from Namhae. The noodles are kneaded with just three ingredients — salt, water, and flour — following the traditional Sanuki method (the udon kingdom), then go through a first and second fermentation before being finished after 48 hours. That's probably why the noodles have such a chewy, springy texture. Isn't that just so much dedication..?!🥹 I'm definitely getting the standalone udon next time .. .ᐟ.ᐟ ![Fresh Sanuki udon noodles served with the set](https://img.superchart.com/images/seongsu-kosi-zaru-soba-karaage-don/seongsu-kosi-zaru-soba-karaage-don-14-5vy8p-900.webp) ![Close-up of crispy-battered king shrimp katsu](https://img.superchart.com/images/seongsu-kosi-zaru-soba-karaage-don/seongsu-kosi-zaru-soba-karaage-don-15-sp2by-900.webp) ## Zaru soba set: cold soba with tonkatsu and inari sushi And to close out the last of summer, the zaru soba set appeared! You can adjust the flavor to taste with scallion, wasabi, and grated radish, and the soba noodles had a springy, chewy texture that was nutty and clean even on its own — but dipped into the cold, umami-rich tsuyu sauce, it was clean, refreshing, and deeply flavorful.. 👍🏻 ![Zaru soba set served with tsuyu dipping sauce](https://img.superchart.com/images/seongsu-kosi-zaru-soba-karaage-don/seongsu-kosi-zaru-soba-karaage-don-16-1ka77-900.webp) Eating it together with the inari sushi and tonkatsu that came with the set made it even better .. seriously, what isn't good here .. !!!!!!! ╥﹏╥ ![Inari sushi and tonkatsu included in the set](https://img.superchart.com/images/seongsu-kosi-zaru-soba-karaage-don/seongsu-kosi-zaru-soba-karaage-don-17-1clwv-900.webp) ![Dipping soba noodles into the tsuyu sauce](https://img.superchart.com/images/seongsu-kosi-zaru-soba-karaage-don/seongsu-kosi-zaru-soba-karaage-don-18-1amt9-900.webp) ## Karaage don, 10,500 won Everything on the menu was delicious, so even though we were full, we ordered the garaage-don anyway — ₩10,500. It's a rice bowl piled with crispy fried chicken thigh, onion sauce, a special sauce, and a generous amount of soft egg. The chicken thigh portions were really generous and the amount of food was huge — it wasn't too heavy or overpowering, and it was seriously filling. I basically demolished the whole thing and nearly burst .. but I was happy .. ![Garaage-don topped with chicken thigh and egg](https://img.superchart.com/images/seongsu-kosi-zaru-soba-karaage-don/seongsu-kosi-zaru-soba-karaage-don-19-gqfpb-900.webp) ## Is Kosi Seongsu Branch worth it for a Seongsu lunch or date? If you're looking for a satisfying lunch in Seongsu, planning a Seongsu date or just wandering around Seongsu and want something delicious, or if you're searching for a good Seoul Forest restaurant or Ttukseom restaurant, I highly recommend the Seongsu tonkatsu spot "Kosi" — you really should visit .ᐟ.ᐟ It might just become the best tonkatsu of your life .. ✨ Next time I'm definitely getting the udon set ..! 🥹 ## Where it is - Kosi Seongsu Branch (코시 성수점) - 31 Sangwon 1-gil, Seongdong-gu, Seoul, South Korea, 1st floor - 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 --- Superchart · https://superchart.com/en/@mullae-quiet-plate/seongsu-kosi-zaru-soba-karaage-don/ · https://superchart.com/llms.txt