Seongsu udon set with inari sushi and whole squid tempura: Kosi

I've been eating a lot of udon lately — I just can't get over how good chewy Japanese-style udon is haha. So when I had a reason to head to Seongsu, I stopped by "Kosi Seongsu Branch," a spot known for udon and tonkatsu.

Where is Kosi Seongsu Branch, and what are the hours?

Kosi Seongsu Branch is at 31 Sangwon 1-gil, 1F, Seongdong-gu, Seoul, right in front of Ttukseom Station Exit 6. It's open daily from 11:00 to 21:00, with a break time from 15:00 to 17:00 and last order at 20:30. There are 2 free parking spots right in front of the store.

Finding Kosi Seongsu Branch outside Ttukseom Station Exit 6

Kosi Seongsu Branch is right in front of Exit 6 of Ttukseom Station, so it was a quick walk from the subway.

There are various menu boards out front, so I could check them before going in. They're written in Japanese, but I could still tell from the boards that it was an udon place.

Inside Kosi Seongsu Branch: solo seats and group tables

Inside Kosi Seongsu Branch, there are big tables alongside a solo bar table, so it works whether you're dining alone or in a group. Every seat has a kiosk, so you can order and pay right where you're sitting.

The inside was bigger and cleaner than I expected — I liked that there were big tables good for groups as well as a bar table good for solo diners. Every seat has its own kiosk for ordering and payment, and there were condiments prepared to go with the various Kosi menu items too.

What we ordered at Kosi Seongsu Branch

What we ordered at Kosi Seongsu Branch was tori-ten bukkake udon, ten-bukkake udon, whole squid tempura, and sweet potato cheese croquette. Besides udon, the menu board also had a good variety of tonkatsu and rice bowls.

We went with udon, but besides udon there were plenty of other options on the menu like tonkatsu and rice bowls.

• Tori-ten bukkake udon
• Ten-bukkake udon
• Whole squid tempura
• Sweet potato cheese croquette

Tori-ten bukkake udon set with salad and inari sushi

We picked the bukkake udon, a cold udon that could be seen as Kosi Seongsu Branch's signature dish. The tori-ten bukkake udon first came topped with three enormous chunks of karaage fried chicken.

It also came with a salad that pairs nicely and a really big inari sushi (fried tofu pocket rice).

Ten-bukkake udon set at Kosi Seongsu Branch

The ten-bukkake udon comes topped with kabocha squash tempura and shrimp tempura over the udon, and it's the same set deal with salad and inari sushi included. I thought the price wasn't too high, but seeing the portion, it really does feel like even better value.

How to eat bukkake udon, and how chewy are the noodles?

Kosi Seongsu Branch's bukkake udon is served cold, and you pour the cold tsuyu sauce that comes alongside it to your taste. Chopped green onion, grated radish, and tempura flakes also come as part of the set — mixing them in brings out extra umami.

Bukkake udon is eaten cold, so you just pour on the cold tsuyu sauce that's served alongside to your liking. I poured mine on until the noodles were just barely submerged and moist.

The tsuyu sauce wasn't as salty as I expected, so it was easy to eat even with a lot poured on.

Looking at the set, there's chopped green onion, grated radish, and tempura flakes at top right that go well mixed into the udon — you can add them to taste and mix it all together for a real boost of umami. I tried adding a bit of everything and dug in right away, and sure enough, being an udon specialty shop really showed — the noodles were incredibly chewy and springy.

And each strand of noodle was so long that eating just one strand at a time would have been enough to fill you up.

Shrimp tempura and kabocha squash tempura

The tempura pieces on top came fried perfectly crisp, almost like delicate snowflake tempura. I'm usually picky about shrimp tempura, but here the sweet shrimp flavor came through more than any oily taste, blending really well with the crispy coating — it was genuinely delicious. The kabocha squash tempura was also really sweet, and I enjoyed it a lot together with the udon.

Whole squid tempura and sweet potato cheese croquette sides

The whole squid tempura and sweet potato cheese croquette we added as sides came in generous multiple pieces, good for sharing. The sweet potato cheese croquette has cheese in the center, so I'd recommend eating it while it's still warm.

We also ordered some fried side dishes — there were really a lot of options, but among them we picked the croquette and squid tempura, which looked the most familiar. They also came in multiple pieces each, so it seemed like a good idea to order them for the table and share bits of everything.

First, the squid tempura was so chewy and tender it really tasted like it was fried from fresh raw squid. It wasn't dried out at all — completely plump — so it was really delicious.

And the sweet potato cheese croquette has cheese right in the center, so I'd recommend eating it while it's warm. The sweet potato was packed in generously, whole and unprocessed, so I could really taste both the sweetness and the nuttiness.