# Tonkatsu with kelp vinegar in Dongjak, Seoul: cheese katsu at Kosi Isu - By Minsol (https://superchart.com/en/@bupyeong-table-card/) - Written Sep 17, 2026 - Local places › Restaurants › Dongjak, Seoul - Sponsored: This is a sponsored post based on an in-store visit. - English edition: https://superchart.com/en/@bupyeong-table-card/koshi-isu-cheese-katsu-mazeudon/ - Also in: [한국어](https://superchart.com/ko/@bupyeong-table-card/koshi-isu-cheese-katsu-mazeudon/index.md) ## In short Kosi Isu Branch is a tonkatsu and udon restaurant right in front of Exit 9 of Isu Station in Dongjak, Seoul. On a weekday lunch visit, cheese katsu at Kosi Isu Branch cost 12,500 won and mazesoba udon cost 11,000 won, served with stretchy melted cheese, rice to mix into the udon at the end, and vinegar steeped with kelp. With plenty of tables and no wait, Kosi Isu Branch is an easy pick near Isu Station even for solo diners. ## Good to know - **Address**: 1st floor, 300 Sadang-ro, Dongjak-gu, Seoul - **Hours**: Daily 11:20-21:00 - **Break time**: 15:20-17:00 - **Last order**: 14:50 and 20:30 - **Cheese katsu**: 12,500 won - **Mazesoba udon**: 11,000 won - **Parking**: 1 hour free in the building parking lot - **Location**: In front of Isu Station Exit 9 (under construction; 3-minute walk from Exit 8) - **Price reference**: ₩12,500 ≈ $9 · ₩11,000 ≈ $7.9 (2026-09-19) *as written by the visitor on Sep 17, 2026* ![Cheese katsu and mazesoba udon at Kosi Isu Branch](https://img.superchart.com/images/koshi-isu-cheese-katsu-mazeudon/koshi-isu-cheese-katsu-mazeudon-01-13diz-1200.webp) I had an errand near Isu Station, so I stopped by Kosi Isu Branch, a well-known tonkatsu spot, for cheese katsu and mazesoba udon (mixed udon noodles). Let's get right into the review~ ## Where is Kosi Isu Branch, and what are its hours? Kosi Isu Branch is on the 1st floor of 300 Sadang-ro, Dongjak-gu, Seoul. It's open daily from 11:20 to 21:00, with a break time from 15:20 to 17:00, and last order at 14:50 and 20:30. ![Exterior of the Kosi Isu Branch building near Isu Station](https://img.superchart.com/images/koshi-isu-cheese-katsu-mazeudon/koshi-isu-cheese-katsu-mazeudon-02-jkt5u-966.webp) ![Entrance view of Kosi Isu Branch](https://img.superchart.com/images/koshi-isu-cheese-katsu-mazeudon/koshi-isu-cheese-katsu-mazeudon-03-q6j36-966.webp) ![Route from Isu Station Exit 8 to Kosi Isu Branch](https://img.superchart.com/images/koshi-isu-cheese-katsu-mazeudon/koshi-isu-cheese-katsu-mazeudon-04-nakxl-966.webp) Kosi Isu Branch is right in front of Exit 9 of Isu Station, so it's very easy to reach by public transit. But Exit 9 is currently under construction, so you'll need to come out through Exit 8 instead — it's still only about a 3-minute walk from there. ### Parking at Kosi Isu Branch If you use the building's parking lot, you get 1 hour free. I came by public transit, but it's nice to know there's parking support even in Seoul — that makes driving there pretty convenient too. ## Ordering cheese katsu (12,500 won) and mazesoba udon (11,000 won) ![Menu board displayed outside Kosi Isu Branch](https://img.superchart.com/images/koshi-isu-cheese-katsu-mazeudon/koshi-isu-cheese-katsu-mazeudon-05-d54fl-938.webp) There's a menu posted outside too, so it was easy to decide what to order before going in. The country-of-origin labeling was also clearly displayed. I ordered the cheese katsu (₩12,500) and the mazesoba udon (₩11,000). I liked that the prices weren't too high either. ## Weekday lunch at Kosi Isu Branch: is there a wait? ![Busy dining hall at Kosi Isu Branch during weekday lunch](https://img.superchart.com/images/koshi-isu-cheese-katsu-mazeudon/koshi-isu-cheese-katsu-mazeudon-06-6oddb-m-966.webp) ![Interior of Kosi Isu Branch with plenty of tables](https://img.superchart.com/images/koshi-isu-cheese-katsu-mazeudon/koshi-isu-cheese-katsu-mazeudon-07-1jdxb-m-966.webp) I visited during weekday lunch, and the place was really packed, probably with office workers from nearby. Still, since there were plenty of tables, there was no separate wait. A lot of people were dining solo too, so it seems like a great spot for a simple solo meal. ![Salt, pepper, sesame, and shichimi seasonings set on the table](https://img.superchart.com/images/koshi-isu-cheese-katsu-mazeudon/koshi-isu-cheese-katsu-mazeudon-08-bu8p7-966.webp) Each table had salt, pepper, sesame, shichimi (seven-spice chili powder), and other seasonings already set out, so it was easy to add whatever suited your taste. Enjoying the food as it's served is nice, but I also liked being able to adjust the flavor with a bit of sauce or seasoning to make it my own — especially for adding seasoning or boosting flavor where a dish needed it. ![Table setting with cheese katsu and mazesoba udon](https://img.superchart.com/images/koshi-isu-cheese-katsu-mazeudon/koshi-isu-cheese-katsu-mazeudon-09-1vth0-966.webp) The cheese katsu and mazesoba udon I ordered both arrived. Looking at them again, the crispy cheese katsu and the appetizing mazesoba udon looked hearty and delicious. I especially love salad, so I was really happy that a generous portion of salad came with the meal. Cleansing my palate with the salad between bites of the crispy cheese katsu made the whole meal even more enjoyable. ## How was the cheese katsu? ![Plate of crispy fried cheese katsu](https://img.superchart.com/images/koshi-isu-cheese-katsu-mazeudon/koshi-isu-cheese-katsu-mazeudon-10-ldetm-966.webp) ![Cross-section of cheese katsu with stretchy cheese pull](https://img.superchart.com/images/koshi-isu-cheese-katsu-mazeudon/koshi-isu-cheese-katsu-mazeudon-11-19prj-966.webp) The cheese katsu had a crispy fried pork cutlet packed with savory, soft cheese inside — the first bite stretched into a long cheese pull, impressive in both looks and taste. The crunchy breading, juicy meat, and rich, savory cheese came together really well for a full-bodied flavor. The mild, creamy cheese made it even more enjoyable to eat. ## Mazesoba udon with rice to mix in at the end ![Mazesoba udon topped with ground meat and garnishes](https://img.superchart.com/images/koshi-isu-cheese-katsu-mazeudon/koshi-isu-cheese-katsu-mazeudon-12-lcbyg-966.webp) ![Udon noodles mixed with sauce](https://img.superchart.com/images/koshi-isu-cheese-katsu-mazeudon/koshi-isu-cheese-katsu-mazeudon-13-o5a0i-966.webp) The mazesoba udon had chewy udon noodles mixed with a savory special sauce, ground meat, and various toppings — full of umami. The sauce soaked well into the noodles, so every bite had a rich flavor, and the savory, slightly spicy kick kept me reaching for more. Plus, after finishing the noodles, you can mix the leftover sauce with rice, which makes for a really filling meal. ![Kelp vinegar served alongside the mazesoba udon](https://img.superchart.com/images/koshi-isu-cheese-katsu-mazeudon/koshi-isu-cheese-katsu-mazeudon-14-1jggc-966.webp) ![Bottle of vinegar containing kelp](https://img.superchart.com/images/koshi-isu-cheese-katsu-mazeudon/koshi-isu-cheese-katsu-mazeudon-15-gjxw7-966.webp) Kelp vinegar came alongside the dish so you could add it to taste — having kelp steeped in the vinegar was an unusual and nice touch. ## Is Kosi Isu Branch worth a visit? I'd recommend Kosi Isu Branch, a great restaurant near Isu Station where you can enjoy everything from crispy, savory cheese katsu to umami-packed mazesoba udon and other Japanese dishes. Whether you want a hearty meal or something a bit different, there's plenty to choose from depending on your taste. Plenty of people dine solo here too, so it's a good spot to visit on your own. ## Where it is - Kosi Isu Branch (코시 이수점) - 300 Sadang-ro, 1st floor, units 126 & 127, Dongjak-gu, Seoul, South Korea - 서울특별시 동작구 사당로 300 1층 126호, 127호 - 37.4844642, 126.9808303 - Google Maps: https://www.google.com/maps/search/%EC%BD%94%EC%8B%9C%20%EC%9D%B4%EC%88%98%EC%A0%90/@37.4844642,126.9808303,17z --- Superchart · https://superchart.com/en/@bupyeong-table-card/koshi-isu-cheese-katsu-mazeudon/ · https://superchart.com/llms.txt