Dongjak Japanese restaurant for toriten bukkake udon: Kosi Isu Branch

Handmade udon and fresh pork loin tonkatsu in Sadang-dong, near Isu Station

Here begins my honest review of a Sadang-dong, near-Isu Station favorite known among locals—and featured on Master of Life—for fresh pork loin handmade tonkatsu and handmade bukkake udon! 🙌🏻

Kosi Isu Branch (코시 이수점), a great spot for ten bukkake udon and fresh pork loin tonkatsu.

Kosi Isu Branch visit information

147-29 Sadang-dong, Dongjak-gu, Seoul

• Daily 11:20–21:00
• Last orders at 14:50 and 20:30
• Break time 15:20–17:00
• Reservations available for parties of 5 or more
• Parking available; 1 hour validated when using the building's underground parking lot
• Separate restrooms for men and women

Weekday-evening wait times and handmade noodles

As you’d expect from a popular Isu restaurant, Kosi Isu Branch has waiting chairs by the entrance. I visited at dinner; turnover was fairly quick, and luckily, since it was a weekday, I got in with no wait 🍀

Kosi’s handmade noodles follow the traditional Sanuki method: a dough of just salt, water, and flour that undergoes a second 48-hour aging process, apparently! 👍🏻

From bukkake udon to tonkatsu: the menu

For the detailed menu—Kosi’s signature bukkake udon, maze udon, kama udon, tonkatsu, donburi rice bowls, gyudon, katsudon, karaage don, fried chicken, tempura, yubu chobap (seasoned tofu pouch sushi), and fried shrimp—please check the photos 📷

A Japanese-style interior that also works for solo dining

Inside, there are window-side counter seats for one, two-person tables, four-person tables, and more. Lots of people were eating alone, so I think it would be great for a solo meal near Isu Station too. The interior has a Japanese feel 🫶🏻

Every table is set with salt and pepper, sesame seeds, utensils, wet wipes, paper cups, and more 👍🏻

A full toriten bukkake udon and tempura spread

Toriten bukkake udon (11.0), plus extra tempura (4.0). It came generously set out with salad, kkakdugi (cubed radish kimchi), danmuji (pickled radish), and a soy dipping sauce for the fried items. Such a neat, satisfying bukkake udon spread. I absolutely love the design of the bowl holding the tsuyu dipping broth 🫶🏻

The beautifully plated handmade udon, karaage, toppings, and even the included yubu chobap and tempura made for a dreamy visual 🫠

How do you eat bukkake udon?

I looked it up because I was curious about both the restaurant and dish names. Kosi refers to elasticity, viscosity, and a chewy texture, while bukkake udon is a cold udon dish eaten by pouring tsuyu over it. Pour Kosi’s soy sauce, brought in from Japan, over the noodles and the ten bukkake udon is complete. Let’s admire that beautiful visual ☺️

Worthy of a Master of Life feature, Kosi’s handmade udon noodles are wonderfully chewy and springy. They pair so well with the tsuyu—really delicious. I’ve fallen for the charms of cold udon, hehe 🫶🏻

The fried items are made with clean oil too, so they’re crisp and light. Kosi’s bukkake udon feels like something I’ll think about regularly 🫠

Assorted cutlets and extra hot udon

Assorted cutlets (14.5), extra udon (3.5).

Kosi’s tonkatsu is made with domestic fresh pork loin, pounded daily and fried to order. The coating is crisp outside, while the loin within is mild and moist—so good 🤍 You can dip it to your taste in tartar sauce, tonkatsu sauce, pink salt, or wasabi 👍🏻

The extra hot udon I added to the handmade tonkatsu meal also had that lively noodle texture, while the broth of Namhae anchovies and kelp had a deep flavor—delicious 🫶🏻

From family gatherings to dates

This is a local favorite where people line up right at opening in Isu as well as at the other branches 🙌🏻 With a spacious 48-seat interior, it’s great for family gatherings, group meals, and dates; this Sadang-dong handmade-udon spot also validates 1 hour of building parking 🫶🏻

I highly recommend Kosi Isu Branch, a great Isu restaurant where you can enjoy handmade bukkake udon and fresh pork loin handmade tonkatsu, completed by time and good ingredients 👍🏻