Udon restaurant near Isu Station with 3,000-won draft beer: Kosi

This weekend's date brought us to Kosi Isu Branch, famous as an Isu Station restaurant :) It's already been featured on the TV show Life's Masters and had its flavor certified, and apparently the udon noodles here are made with just three ingredients — salt, water, and flour.

Honestly I'm not a huge udon person, but Kosi Isu Branch is especially known for its chewy noodles, so we decided to check it out.

But the udon here... is genuinely delicious...!!! Even though I said I'm not that into udon, it was incredibly chewy, and my partner — who also doesn't usually enjoy noodle dishes that much — finished every single strand without leaving a bit.

Where is Kosi Isu Branch, and its hours and parking

Kosi Isu Branch is located at 300 Sadang-ro, 1st floor, Units 126–127, 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 orders at 14:50 and 20:30.

• Address: 300 Sadang-ro, 1st floor, Units 126–127, Dongjak-gu, Seoul, South Korea
• Hours: Daily 11:20–21:00 (break time 15:20–17:00)
• Last order: 14:50, 20:30
• Parking: Enter 'Isu Xi' in navigation to park on B2 or B3 (1 hour free at building's underground lot)

Once you reach the address, you'll see a big ribbon decoration on the window, along with an explanation that Kosi Isu Branch's udon uses only salt, water, and flour. Apparently the noodles also go through more than two days of aging, which makes them even chewier and springier.

In front of the store, there's a display showing the current menu, with photos making it easy to see the cold udon, hot udon, tonkatsu, and donburi options.

Is there a wait at 8pm on a Saturday? Inside Kosi Isu Branch

Even though we visited around 8pm on a Saturday, Kosi Isu Branch already had quite a few customers. My partner lives near Isu Station and says there's a wait during peak meal times.

We stayed until nearly closing at 8:50pm, and even during that stretch, another 4-5 groups came in. That's how popular Kosi Isu Branch is as an Isu Station favorite. Also, while the photos might make the interior look a bit cramped, it's actually quite spacious and comfortable with 48 seats.

How to order at Kosi Isu Branch and what we ordered

Ordering and payment were done right at the table. The menu was divided into hot udon (kama udon), cold udon, tonkatsu, donburi, sides, and drinks — we ordered toriten bukkake udon from the cold udon section, mixed tonkatsu, and two 300ml draft beers.

Draft beer is a must with tonkatsu!! Once we picked everything, we just pressed pay right at the table and it was all done at once.

Spoons, chopsticks, and wet wipes were all neatly set out, and while we sipped water, the draft beer arrived quickly.

The draft beer came out first! Even at 300ml, it felt like a decent amount. And at just ₩3,000, it was totally affordable. Freshly poured beer was perfect for cooling down on a hot summer day.

And the various seasonings sitting beside the table! There was sesame, chili flakes, and salt/pepper, so it was easy to adjust seasoning if needed. We didn't add anything extra since the dishes were already perfectly seasoned.

What is toriten bukkake udon?

The first dish to arrive was toriten bukkake udon! Toriten bukkake udon is a cold udon-style dish with fried chicken (toriten) placed on top of cold udon noodles, mixed with tsuyu sauce.

So three large pieces of fried chicken were topped on it, and the sauce was provided separately in a bottle. Even the udon here is made in the traditional Sanuki style, which apparently makes the noodles even chewier.

The inari sushi (seasoned fried tofu rice) that came as a default side was quite large compared to my hand, and the cabbage was fresh with no wilted or bruised spots. In particular, the sauce wasn't overly sweet, so it didn't overpower the udon and let us enjoy it cleanly.

The tsuyu sauce was also served cold in a bottle, so pouring it over the udon at the start made for a refreshingly cool first bite.

A table full of udon and tonkatsu!

Mixed tonkatsu came as fillet and shrimp (cheese katsu sold out)

Kosi Isu Branch's mixed tonkatsu also came piled high on the plate :) However, when we visited, the cheese option was sold out, so it came as fillet + shrimp katsu instead.

Instead of inari sushi, the mixed tonkatsu came with plain rice, along with separate sauces for the tonkatsu and shrimp katsu plus a light broth. I especially love pairing food with wasabi and salt, and Kosi Isu Branch served both alongside.

When we cut off the head of the shrimp katsu, an impressively huge shrimp was revealed!

Even when cut in cross-section, the batter wasn't thick — it was fried to just the right thinness and crispiness, letting the shrimp's natural flavor shine through. As you can see in the photo, it was packed full inside, and every bite delivered great shrimp aroma and texture!

Try dipping it deep into the tonkatsu sauce too 👍

Besides the shrimp katsu, the fillet katsu also came along! Fillet is the tenderloin cut, which is low in fat and mild in flavor, and apparently it's often used for frying tonkatsu.

But since it's low in fat, poor-quality meat tends to turn out dry... here, though, it was moist and light, so even by the last bite it never felt greasy or heavy! The batter thickness was just right too, staying crispy all the way through.

Are the udon noodles at Kosi really that chewy?

After taking plenty of photos of the tonkatsu, I poured tsuyu over the toriten bukkake udon and it looked even more delicious..!

The fried chicken pieces were big, with three included, so the portion was never lacking.

And it really was... genuinely delicious... Many of you have probably seen this on other blogs, but the noodles were truly chewy, springy, and bouncy...ㅠㅠㅠㅠ.... I finally understood why everyone insists you have to order the cold udon here...

I'm not writing this because it was a sponsored visit — I'm leaving this review because it was genuinely delicious ㅠㅠ..!!

As I mentioned, I'm not someone who normally seeks out udon, and at places that don't do it well, you often get a flour smell or noodles that snap apart easily, right...? But here, the noodles were long, and even when I pulled hard trying to eat one strand at a time, they wouldn't break easily...! Eventually I even used scissors to cut them. That's how chewy and springy they were!

Eating the tonkatsu and udon along with the cabbage salad and inari sushi filled us up completely, even without adding any extra sides!

Facilities and final verdict on Kosi Isu Branch

With in-store wifi and a restroom in the building, we could eat comfortably throughout the meal at Kosi Isu Branch, our Isu Station favorite..!! Even though my partner doesn't especially love noodles, they mentioned having been here before. They liked it back then, and now we came together again.

If you've had prejudices about udon like I used to, you have to try this place!! Out of all the sponsored blog visits I've done, this ranks among the very best.