Gwanak udon restaurant, 9,000-won bukkake udon after work: Kosi

In short

Kosi Seoul National University Entrance Branch is a bukkake udon specialist near Exit 5 of Seoul National University Entrance Station in Gwanak, Seoul. Visiting after work on a Monday with a friend, the writer ordered bukkake udon for 9,000 won and tori tempura bukkake udon for 11,000 won as single dishes, and even those came with one inari sushi (fried tofu rice pocket) and a salad. Pouring only half the tsuyu dipping sauce at first, then the rest later, made Kosi's noodles a light, clean meal worth returning for.

A bowl of Kosi's bukkake udon

Good to know

Location
Near Exit 5, Seoul National University Entrance Station (101, 466 Bongcheon-ro, Gwanak-gu, Seoul)
Hours
11:00-20:50
Break time
15:00-17:00
Bukkake udon
9,000 won
Tori tempura bukkake udon
11,000 won
What a single dish includes
Main + 1 inari sushi + salad
Ordering and payment
Order by table tablet, prepay at your seat
Seating
Window bar seats for solo diners; waiting area available

as written by the visitor on Sep 20, 2026

I made a lot of cold udon at home this summer, but there's only so much homemade you can take before you start craving the real thing. Then I found a place that does bukkake udon properly, near Seorip-eun-ipgu — I mean, near the entrance — and went with a friend right after work!

Exterior of Kosi Seoul National University Entrance Branch near Exit 5

Where is Kosi, and how long is the Monday evening wait?

Kosi Seoul National University Entrance Branch is just a short walk from Exit 5 of Seoul National University Entrance Station. There's a waiting area too, so lining up isn't bad. We went straight after work and got in with no wait, but by the time we left there were people waiting. It was a Monday — apparently good food doesn't care what day it is, haha.

Entrance and waiting area of Kosi Seoul National University Entrance Branch
Interior of Kosi Seoul National University Entrance Branch
Interior view of Kosi showing the half-open kitchen

The space is very clean, and the half-open kitchen means you can see a lot of the prep and plating happening. Places with open kitchens always feel a bit more trustworthy to me, haha. It was that post-work hungry hour, so every time a dish came out I silently prayed it was ours, haha.

Menu board for bukkake udon at Kosi Seoul National University Entrance Branch
Menu board listing tonkatsu and rice bowl dishes at Kosi
Menu information including hot noodle soup at Kosi

Kosi menu and prices: bukkake udon 9,000 won, tori tempura bukkake 11,000 won

Kosi's menu centers on cold bukkake udon, but there are also tonkatsu dishes and rice bowls — and of course hot noodle soups too! With such a variety of hearty Japanese dishes, it seems like a good spot to visit regardless of the season.

Ordering via the table tablet

We ordered the bukkake udon and the tori tempura bukkake udon! At 9,000 won and 11,000 won, they're just right for a single meal. Most restaurants around Sharosu-gil charge upward of 13,000 won, so this felt like a bargain, haha haha. You order through the tablet at the table, and you can pay right there in advance!

Table setting at Kosi

Before the food arrived, the table already had salad dressing, pepper, sesame seeds and other condiments set out.

Table condiments including salad dressing, pepper and sesame seeds

Inari sushi and salad with a single dish at Kosi: how much food do you get?

The food finally arrived! At Kosi, ordering a single item gets you the main dish plus one inari sushi (fried tofu pocket rice) and a salad. It's just the right amount for an average adult woman. I stole a bite of my friend's tori tempura and left completely full, but honestly, the bukkake alone would've been plenty for a solo visit!

Bukkake udon single order served with inari sushi and salad
Full spread of the bukkake udon single-item order at Kosi

As expected... the noodles were on a totally different level from the packaged cold udon you buy at home. (Obviously, but still.) They were so springy and chewy they practically slipped off the chopsticks!!

Springy noodles of the bukkake udon

The inari sushi!! I hadn't expected it as a side, which somehow made it taste even better — I wanted to order more, haha. Between bites of the cold bukkake, whenever I got a little chilly I'd pop in a bite of inari, and the combo worked really well. Without it, the meal would've felt kind of plain!

Single piece of inari sushi included with the single order

For the salad, you just drizzle on the dressing from the table. It's crisp and refreshing, and really wakes up your appetite before diving into the bukkake, haha.

Side salad with dressing drizzled on
A bowl of Kosi's bukkake udon
Cold tsuyu sauce served separately

How to eat bukkake udon: pour only half the tsuyu first

Kosi's bukkake udon comes with the tsuyu sauce served separately like this. Super cold! You're meant to pour it in and mix it all up, but instead of pouring it all at once, I poured about half first to taste the noodles on their own, then added the rest later. If you want the full, classic bukkake experience though, pouring all the tsuyu in from the start is probably the way to go!

It was a hot day, and eating the cold bukkake instantly cooled my whole body down. I'm personally not a big fan of naengmyeon (cold buckwheat noodles), so I tend to prefer cold noodle soups or cold udon instead — the sauce here wasn't overpowering at all, and it was light and clean, which I really appreciated!!

Bukkake udon mixed with the tsuyu sauce
Noodles lifted up from the bukkake udon

Tori tempura bukkake udon: three pieces of fried chicken for a heartier meal

And then there's the tori tempura bukkake udon my friend ordered! Tori ten means chicken tempura — it's the same base bukkake udon topped with three pieces of fried chicken. The udon itself tastes the same, so this is the one to get when you want something more filling. Three pieces of fried chicken on top of udon is a lot, so I ate one of them for her, haha — the chicken was tender and the coating was thin and crispy, so good. If I visit on a hungrier day, I think I'll get the tori tempura bukkake udon myself. Honestly, even after being full, I found myself wanting one more piece of tori tempura, haha.

Tori tempura bukkake udon topped with three pieces of fried chicken

Is Kosi good for solo dining, and would the writer go back?

There's a coupon for a free side dish if you write a Naver review, so download it before you go and mention it in advance. As a cold udon lover... this kind of place is just so good!! It's great in summer for the refreshing chill, and honestly cold udon is pretty tasty even in winter, bundled up in a long padded coat.

Making it myself was always kind of a hassle, so finding a cold udon spot like this near Seoul National University Entrance is great! I'll have to time my next visit for a slower hour to avoid the wait. It was too crowded to photograph every seat, but there were quite a few window bar seats too, so solo diners can eat comfortably, and table turnover seemed pretty quick.

Beyond bukkake, there's tonkatsu, katsudon and other options, so it's also a good spot to bring a friend who isn't into cold udon. Glad to have found one more good restaurant near Seoul National University Entrance Station!

Where it is

Kosi Seoul National University Entrance Branch코시 서울대입구점

101, 466 Bongcheon-ro, Gwanak-gu, Seoul, South Korea서울특별시 관악구 봉천로 466 101호

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