Udon and katsu spot at Isu Station, after-work dinner with sons: Kosi
In short
Kosi Isu Branch (코시 이수점) is an udon and Japanese tonkatsu restaurant near Exit 9 of Isu Station in Dongjak, Seoul, serving house-made noodles in the traditional Sanuki style. After work, the blogger stopped in with two sons for the signature mixed katsu, a toriten bukkake udon set, maze udon and inari sushi; there was a wait after 6:30 PM. Kosi Isu Branch is a good Isu Station pick with kids whenever you crave springy bukkake udon like the kind in Osaka.
Good to know
- Location
- Units 126 and 127, 1F, 300 Sadang-ro, Dongjak-gu, Seoul (near Isu Station Exit 9)
- Hours
- Daily 11:30–21:00 (check the break time before you go)
- Parking
- 1 hour free in the building's underground car park
- Seating
- About 48 seats in the main dining room, plus a bar counter
- Wait
- Expect a wait after 6:30 PM; lemon water is offered while you wait
- Ordering
- Order at the kiosk
- What we ordered
- Signature mixed katsu, toriten (chicken tempura) bukkake udon set, maze udon (mixed udon), 2 inari sushi (rice in fried tofu pouches)
as written by the visitor on Aug 5, 2026
In a hot, humid summer like this, just standing over the stove at home is torture... 😭 And for a mom of two high-energy boys, the best eating-out pick with kids is obviously udon and crispy tonkatsu (breaded pork cutlet), which nobody ever turns down, right?! 🤩
Suddenly I started missing the cold udon I first had on a trip to Osaka in my late 20s (what a sudden bout of sentimentality, haha). I'd been wandering aimlessly and found a local spot in the underground mall at Osaka Station, and I got so nostalgic for that springy, chewy bukkake udon (udon with concentrated sauce poured over). 🥹
So after work I grabbed my two boys by the hand and ran to the place that serves udon and tonkatsu made the traditional Sanuki way: Kosi Isu (코시 이수)! 🏃♀️🏃🏃♂️💨
The slower it goes, the deeper the flavor.
As Kosi's philosophy says, the udon noodles take 48 hours to make, the soy sauce is ready after 24 hours, and the broth takes more than 12 hours. And they hand a cup of lemon water to guests worn out by the heat while they wait. So thoughtful 🥲
Kosi Isu Branch location and hours
📍 Location: near Exit 9 of Isu Station, Dongjak, Seoul. It's so close to the station that it's perfect for dropping in on the way home! Even when you're dragging a tired body after work, it's really easy to get to. Address: 300 Sadang-ro, 1st floor Units 126 and 127, Dongjak-gu, Seoul, South Korea.
⏰ Hours: daily 11:30–21:00 (be sure to check the break time!)
Lunch peak is packed with office workers, and in the evening there are lots of families like mine and people stopping by after work. There was a wait after 6:30 PM, so keep that in mind when you visit! 😉
🚘 Parking: 1 hour free in the building's underground parking lot
Atmosphere and seating: good with kids, good solo
The moment I walked into Kosi Isu, the clean, tidy interior won me over. 🌿
The hall has a generous 48 or so seats, and the tables are spaced comfortably, so eating with the kids was no trouble at all. There's also a well-made bar table area, so you can eat comfortably on your own without feeling awkward! 🤓 In fact it's very popular with people looking for a solo-dining spot near Isu Station. 👍
Menu and ordering
📜 Menu
As a udon and tonkatsu specialist, the menu is really full, from noodle types to katsu dishes! You order easily at a kiosk, so even deciding what to get with the kids felt relaxed.
Signature mixed katsu: the textbook crispy outside, juicy inside
🍤 The signature mixed katsu is the textbook crispy-outside, juicy-inside cutlet! They say the meat is aged for 24 hours and cooked only once you order. The batter isn't overly thick and the meat is really thick, so the juice when you bite in is amazing. 🤤
And when you dip it in the salt that comes alongside, that harmony of fat and salt, you know what I mean, right? 😉 And look at the size of that shrimp katsu! Crispy texture and tender shrimp! 🍤
Toriten bukkake udon set: that Osaka taste
🍜 The toriten bukkake udon set was the very dish I'd been looking forward to! It brought back my Osaka memories from my twenties. You pour the tsuyu (soy-based dipping sauce) over and toss it all together, and the chewiness and springiness of the noodles is just crazy... 👍
The combo with the crispy toriten (fried chicken) served alongside was perfect too. Slightly soaked in that sweet, Japanese-style tsuyu broth and just a little soggy... this flavor wipes away the whole tired day!
Mazesoba-style udon and inari sushi
🍝 I actually ordered the mazeudon (brothless udon mixed with sauce) for my husband, but my second son, who'd been crying that he wouldn't eat, finished a whole bowl. Don't tell anyone.
You mix it into the rich, thick special meat sauce, bursting with savory flavor! Spicy-sweet and addictive!!!
🍙 The two inari sushi are big and stuffed full. They're a filling side to go with udon or tonkatsu.
Overall verdict
🤍 Thank you to the kind owner and staff 😉 They gave the kids Haribo after the meal, which made it an even happier memory 🫢💕
👨👩👧👦 Satisfaction: ★★★★★ Crispy handmade katsu the kids devoured like it was a battle, plus springy bukkake udon that brings back my Osaka memories in my twenties. A combo that can't miss!
- 🌿 Atmosphere: clean and tidy through and through! Wide table spacing makes it great for family meals, and the well-made bar table makes it a strong pick for dining solo near Isu Station!
- 🚗 Accessibility: near the station, so it's the ideal route for a quick meal on the way home!
- 🎯 In one line: when you need healing after a tiring commute, a tasty meal to recharge your energy, a great Isu Station restaurant!
💡 Recommended for: office workers looking for lunch near Isu Station, anyone missing good tonkatsu around Isu Station, and working-mom neighbors who want to eat out comfortably with kids. I recommend it with confidence! ❤️
Where it is
300 Sadang-ro, 1st floor Units 126 and 127, Dongjak-gu, Seoul, South Korea서울특별시 동작구 사당로 300 1층 126호, 127호
