Seongsu Japanese restaurant for hot bukkake udon: Kosi

Ttukseom Station tonkatsu and udon after a Seongsu date

I visited for lunch after a weekend date in Seongsu with my boyfriend. It is about a 13-minute walk from Seongsu Café Street, so it was nice to stroll over slowly while on our date. We went at lunchtime and luckily there was no wait when we arrived, so we got straight in. But not long after we entered, customers began trickling in and a line formed!

Kosi Seongsu Branch location

A menu divided into cold and hot udon

Kosi menu

Kosi had quite a varied menu. The main dishes were Sanuki udon and tonkatsu, and the udon was divided into cold and hot options. We ordered without looking closely at the menu, so after we ordered, a staff member asked, “You ordered the hot udon, right?” When we looked again, we realized the cold and hot udon were listed separately! Honestly, it was our first time trying bukkake udon itself, so we ordered without really knowing what style it was, haha.

So if it is your first visit to Kosi and you have a particular dish in mind, I recommend checking the menu before you go!

Ordering assorted cutlets and fried chicken thigh

We ordered the assorted cutlets and fried chicken skin as a side, then chose hot tempura bukkake udon and added shrimp tempura. Each dish arrived neatly arranged on its own tray.

We started with the assorted cutlets. It included two pieces of cheese cutlet, along with handmade tonkatsu made by seasoning the pork and aging it for 24 hours.

Just looking at them, the outside was fried beautifully crisp, and they looked absolutely delicious!

The cheese cutlet in particular was packed with mozzarella, so the cheese spilled out and stretched on and on.

I thought the cheese cutlet might be overly rich, but it was less rich than expected—nutty and tasty.

The tonkatsu pork was tender rather than dry, and it did not get tiring to eat.

The fried chicken skin we ordered as a side was generously sized, and its outside was completely crispy, so the texture was great!

And it was actually chicken thigh rather than chicken skin. The inside was tender and juicy rather than dry, and the meat was seasoned just right, so it was delicious even without dipping it in sauce.

My first hot tempura bukkake udon

Next was the tempura bukkake udon. It also came with one piece of inari sushi (sweet tofu-pocket sushi) as part of the standard set.

Since it was our first time trying bukkake udon, we were a little startled at first when it arrived without broth, haha.

Apparently, bukkake udon is not a brothy udon; it is a style where you pour udon tsuyu (dipping sauce) over the noodles and mix it together! After a staff member explained it, we added all of the soy sauce and mixed it well with the noodles before trying it.

The noodles arrived warm and were incredibly chewy. Kosi says it makes its udon with udon tsuyu using soy sauce imported from Japan and in the traditional Sanuki style. I had high expectations because these udon noodles were even featured on Master of Living, and they really did have a different texture from ordinary udon. They were bouncy yet chewy, and so delicious.

The tempura was crispy too, never soggy, and perfect with the udon noodles.

A compact interior for solo meals or dates

Kosi Seongsu Branch had a clean, compact atmosphere overall. There were counter-style seats that were great for dining alone,

as well as tables for two to four people, making it a good option for solo meals, dates, or visits with friends.