# Seongsu udon and tonkatsu spot with Sanuki fresh noodles: Kosi Seongsu - By Garam (https://superchart.com/en/@local-order-book/) - Written Sep 16, 2026 - Local places › Restaurants › Seongdong, Seoul - Sponsored: This post is based on a visit provided by the restaurant. - English edition: https://superchart.com/en/@local-order-book/koshi-seongsu-sanuki-bukkake-udon-katsu/ - Also in: [한국어](https://superchart.com/ko/@local-order-book/koshi-seongsu-sanuki-bukkake-udon-katsu/index.md) ## In short Kosi Seongsu Branch is a Japanese restaurant on Sangwon 1-gil in Seongdong, Seoul, serving Sanuki-style handmade fresh udon and tonkatsu made with domestic fresh pork loin. The writer ordered the signature bukkake udon as the main and added crispy tonkatsu, which came with inari sushi (fried tofu rice pockets), salad and a cheese croquette, while a friend ordered the udon on its own. The chewy noodles and thick cutlet balanced each other well, making Kosi Seongsu Branch a Seongsu tonkatsu place best ordered as a set. ## Good to know - **Address**: 31 Sangwon 1-gil, 1st floor, Seongdong-gu, Seoul - **Parking**: 2 free spaces in front of the restaurant - **Hours**: Daily 11:00–21:00 - **Break time**: 15:00–17:00 - **Last order**: 20:30 - **Ordering**: Tableside kiosk - **Set option**: Udon as the main with a tonkatsu side, or tonkatsu as the main with udon added *as written by the visitor on Sep 16, 2026* ![Main photo of the bukkake udon and tonkatsu set at Kosi Seongsu Branch](https://img.superchart.com/images/koshi-seongsu-sanuki-bukkake-udon-katsu/koshi-seongsu-sanuki-bukkake-udon-katsu-01-7t69d-1200.webp) ## What is Kosi Seongsu Branch, the Sanuki udon and tonkatsu restaurant in Seongsu? Kosi Seongsu Branch is a Japanese restaurant serving udon and tonkatsu at 31 Sangwon 1-gil, 1st floor, Seongdong-gu, Seoul. Yesterday I wanted proper Japanese food, so I headed to Kosi Seongsu Branch, known as one of the best tonkatsu spots in Seongsu. Turns out this place even appeared on the TV show Master in the House, and they use only handmade fresh noodles made in the 800-year-old Sanuki tradition. By the way, the name 'Kosi' is a Japanese word for the chewiness and springiness of noodles. Since the tonkatsu is also made only with domestic fresh pork loin, I went in with high expectations! - 📍31 Sangwon 1-gil, 1st floor, Seongdong-gu, Seoul (2 free parking spots in front) - Daily 11:00–21:00 - Break time 15:00–17:00 - Last order 20:30 ![Wood-toned exterior of the Kosi Seongsu Branch building](https://img.superchart.com/images/koshi-seongsu-sanuki-bukkake-udon-katsu/koshi-seongsu-sanuki-bukkake-udon-katsu-02-xbr4q-966.webp) ![Entrance and photo menu signboard at Kosi Seongsu Branch](https://img.superchart.com/images/koshi-seongsu-sanuki-bukkake-udon-katsu/koshi-seongsu-sanuki-bukkake-udon-katsu-03-1mf2v-966.webp) The clean, warm wood-toned exterior stood out along with the tidy Japanese-style atmosphere. Seeing the appetizing photo signboard set up outside, I was already happily agonizing over what to order before even walking in. ![Menu signboard set up outside Kosi Seongsu Branch](https://img.superchart.com/images/koshi-seongsu-sanuki-bukkake-udon-katsu/koshi-seongsu-sanuki-bukkake-udon-katsu-04-44bpl-966.webp) ![Interior seating at Kosi Seongsu Branch](https://img.superchart.com/images/koshi-seongsu-sanuki-bukkake-udon-katsu/koshi-seongsu-sanuki-bukkake-udon-katsu-05-1apvb-m-966.webp) ![Bar table seating at Kosi Seongsu Branch](https://img.superchart.com/images/koshi-seongsu-sanuki-bukkake-udon-katsu/koshi-seongsu-sanuki-bukkake-udon-katsu-06-1k981-966.webp) ![Clean Japanese-style dining hall at Kosi Seongsu Branch](https://img.superchart.com/images/koshi-seongsu-sanuki-bukkake-udon-katsu/koshi-seongsu-sanuki-bukkake-udon-katsu-07-1ytlm-966.webp) ### Bar seats at Kosi Seongsu Branch that work for solo diners Walking inside, there's a bar table along with comfortable seating, so it looked like a great spot to grab lunch or eat solo near Seongsu-dong without any pressure. I liked the overall pleasant and clean atmosphere. ![Table setting and dressing bottle at Kosi Seongsu Branch](https://img.superchart.com/images/koshi-seongsu-sanuki-bukkake-udon-katsu/koshi-seongsu-sanuki-bukkake-udon-katsu-08-keml5-966.webp) ![Tableside kiosk screen at Kosi Seongsu Branch](https://img.superchart.com/images/koshi-seongsu-sanuki-bukkake-udon-katsu/koshi-seongsu-sanuki-bukkake-udon-katsu-09-iwfva-966.webp) ![Udon and tonkatsu set menu board at Kosi Seongsu Branch](https://img.superchart.com/images/koshi-seongsu-sanuki-bukkake-udon-katsu/koshi-seongsu-sanuki-bukkake-udon-katsu-10-13sul-966.webp) ## How does the set menu work at Kosi Seongsu Branch? You order through the kiosk at your table! What's especially appealing here is the set menu structure. If you order udon as your main, you can add crispy tonkatsu as a side, and conversely, if you order tonkatsu as your main, you can add udon to make it a hearty meal. Being able to reasonably taste both signature menu items made this feel like the top choice for value among Seongsu tonkatsu restaurants. ![Set menu ordering screen at Kosi Seongsu Branch](https://img.superchart.com/images/koshi-seongsu-sanuki-bukkake-udon-katsu/koshi-seongsu-sanuki-bukkake-udon-katsu-11-h3bg3-966.webp) We ordered the signature bukkake udon as our main. My friend ordered just the bukkake udon on its own, ![Single order of bukkake udon served on a tray](https://img.superchart.com/images/koshi-seongsu-sanuki-bukkake-udon-katsu/koshi-seongsu-sanuki-bukkake-udon-katsu-12-fz020-966.webp) while I added the crispy tonkatsu on top. It came out on a neat tray packed full with sauce, salad, tonkatsu, and fried tofu rice balls — just looking at it felt filling. Even though I've been eating a lot less lately... just udon alone somehow wouldn't have been satisfying enough... adding the tonkatsu was a genius move! ![Tray with tonkatsu, fried tofu rice balls and salad](https://img.superchart.com/images/koshi-seongsu-sanuki-bukkake-udon-katsu/koshi-seongsu-sanuki-bukkake-udon-katsu-13-1jnru-966.webp) The default salad sauce seemed to be a fruit-based dressing, and it was really refreshing. The dressing was also set out on the table so you could pour on as much as you wanted, which was another nice touch.👍 ![Basic salad topped with fruit dressing](https://img.superchart.com/images/koshi-seongsu-sanuki-bukkake-udon-katsu/koshi-seongsu-sanuki-bukkake-udon-katsu-14-pnr6w-966.webp) ## How were the bukkake udon noodles and tsuyu sauce? The visual of the bukkake udon was insane! You just pour the tsuyu sauce generously over the noodles, which look plump and bouncy just from looking at them. ![Bukkake udon noodles drizzled with tsuyu sauce](https://img.superchart.com/images/koshi-seongsu-sanuki-bukkake-udon-katsu/koshi-seongsu-sanuki-bukkake-udon-katsu-15-kmiie-966.webp) You mix it well with the tenkatsu (tempura bits), scallions, and grated radish that come with it by default! The moment I took my first bite of noodles, I couldn't help but be impressed. The bounciness and chewiness of the noodles were exactly like the texture I had in Japan. The noodles were soaked through with a savory, slightly salty tsuyu, giving a clean yet deep flavor. ![Bukkake udon mixed with tenkatsu and grated radish](https://img.superchart.com/images/koshi-seongsu-sanuki-bukkake-udon-katsu/koshi-seongsu-sanuki-bukkake-udon-katsu-16-1m18s-966.webp) ### Fresh pork loin tonkatsu and cheese croquette added to the set The tonkatsu that came with the set held up in quality against dedicated handmade tonkatsu specialty shops. Living up to its reputation as a true Seongsu tonkatsu restaurant, the breading was as crispy as a cracker and the meat was thick with juices still intact. The meat was really thick so it had great bite, and the portion was generous — I really enjoyed it. ![Cross-section of a thick fresh pork loin tonkatsu](https://img.superchart.com/images/koshi-seongsu-sanuki-bukkake-udon-katsu/koshi-seongsu-sanuki-bukkake-udon-katsu-17-1r22c-966.webp) The cheese croquette served on the side was also so delicious! Being able to eat savory, crispy handmade tonkatsu together with chewy, cool bukkake udon at the same time!! The balance was perfect👍 ## Is Kosi Seongsu Branch worth a visit? Final verdict Thanks to the thick tonkatsu, I felt satisfyingly full, and combined with the perfect texture of the noodles, this is a place I'd definitely recommend ordering as a set among Seongsu tonkatsu restaurants! It's a restaurant that has all three elements down — taste, portion, and price — so I think I'll be visiting often whenever I go to Seongsu-dong from now on. If you want to enjoy thick, crispy handmade cutlets and chewy noodles all at once, be sure to visit Kosi Seongsu Branch, a Seongsu tonkatsu restaurant! ## Where it is - Kosi Seongsu Branch (코시 성수점) - 31 Sangwon 1-gil, 1st floor, 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 --- Superchart · https://superchart.com/en/@local-order-book/koshi-seongsu-sanuki-bukkake-udon-katsu/ · https://superchart.com/llms.txt