Ttukseom Station udon restaurant: tempura bukkake udon set at Kosi

Kosi Seongsu Branch

I visited Kosi's Konkuk branch a while back and the udon noodles were really my kind of thing — I kept thinking about going back for more. So this time I headed to the Seongsu branch instead. Here's my review of Kosi Seongsu Branch.

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

Kosi Seongsu Branch is a Sanuki udon and handmade tonkatsu restaurant at 31 Sangwon 1-gil, 1F, Seongdong-gu, Seoul, near Ttukseom Station. Hours are 11:00–21:00, with a break time from 15:00–17:00 and last order at 20:30.

• Address: 31 Sangwon 1-gil, 1F, Seongdong-gu, Seoul
• Hours: 11:00–21:00
• Break time: 15:00–17:00
• Last order: 20:30
• Near Ttukseom Station
• Takeout/delivery available
• Bar seats / solo dining fine
• Baby chairs available
• Table ordering, card payment available

From the outside alone, Kosi Seongsu Branch has that unmistakable Sanuki udon restaurant vibe. A big wooden sign and wood-toned exterior read "Sanuki udon & handmade tonkatsu," so you know exactly what you're in for before stepping in.

There's a photo of the signature menu and a full menu board right by the entrance, so it's easy to check prices and portions before going in.

That said, there's usually a wait during lunch peak, so if you'd rather skip the line, aiming for a slightly later lunch might be the move.

Seats at Kosi Seongsu Branch: is solo dining in Seongsu comfortable?

The dining room isn't huge, but the seating mix is solid: tables, counter seats facing the kitchen, and wall-side bar seats. That made solo dining feel completely comfortable.

The space is done up in white and wood tones, giving off a clean, Japanese-style udon shop feel. The footprint itself wasn't as big as I expected, but the seating arrangement made up for it.

Beyond the table seats for groups, there are counter seats facing the kitchen and wall-side bar seats, which makes this a solid pick if you're hunting for a solo-dining spot in Seongsu. When I visited, eating alone didn't feel awkward at all.

Sesame, salt, and shichimi (Japanese seven-spice blend) are set out on the table too, so you can season the food to your own taste.

Kosi Seongsu Branch menu: à la carte or full set?

The menu at Kosi Seongsu Branch spans cold udon like bukkake udon, ten-bukkake udon, and tori-ten bukkake udon, hot udon like kake udon and ebi-ten kake udon, plus kama udon and maze udon. Each udon can be ordered à la carte or as a full set.

The menu had more options than I expected. There's cold udon like bukkake udon, ten-bukkake udon, and tori-ten bukkake udon, hot udon like kake udon and ebi-ten kake udon, plus kama udon and maze udon. The tonkatsu (breaded pork cutlet) side is just as varied — you can choose from plain tonkatsu, a mixed katsu plate, cheese katsu, or a half-and-half set.

What I really liked was that you can order the udon either à la carte or as a full set. If you just want noodles, go à la carte; if you want a heartier meal with tonkatsu included, go for the set.

What I picked was the tempura bukkake udon set. Ten-bukkake udon comes with shrimp tempura and pumpkin tempura, and ordering it as a set adds tonkatsu, which made it a great way to sample Kosi's signature dishes all at once.

Tempura bukkake udon set: how were the noodles and the tempura?

Kosi Seongsu Branch's tempura bukkake udon set arrives as a full spread — cold udon, shrimp tempura, pumpkin tempura, inari sushi (fried tofu pocket rice), and tonkatsu. What stuck with me most was the noodles: much thicker and chewier than regular udon, true Sanuki-style.

It comes out as a fully loaded tray — more generous than I expected, right?

First up, the bukkake udon I'd been most excited for! I poured on a generous amount of tsuyu (dipping sauce), then added scallions and grated radish to taste. The noodles were, again, the standout — much thicker than typical udon, springy the moment you bite in, and getting chewier the more you chew. Honestly, these noodles are a big part of why I came all the way back from the Konkuk branch to Seongsu.

True to its "ten-bukkake" name, the tempura can't be skipped. The shrimp tempura in particular had long, plump shrimp inside, as you can see in the photo. The batter was crisp on the outside while the shrimp stayed springy inside — great to eat between bites of cold udon.

The pumpkin tempura that came alongside it was also fried cleanly. Alternating between the chewy cold udon and the warm, crisp tempura gave a clear contrast in texture, so it never got tiring even by the end.

The inari sushi that came as part of the base set was a nice bonus too! The sweet fried tofu and lightly salted rice made a good sweet-salty combo, great to pop one in between bites of udon.

The thick pork loin tonkatsu that comes with the set

Kosi Seongsu Branch's tonkatsu leans closer to the traditional Japanese style, cooked all the way through, rather than the pink, low-temperature-cooked cutlets you see a lot these days. It was thick but not overly greasy, which paired well with the cold udon.

And now for the set's other star: the tonkatsu! Picking up a piece, the meat is noticeably thick. Rather than the pink, low-temp-cooked cutlets popular these days, this is closer to a traditional Japanese-style tonkatsu, cooked through completely.

The meat wasn't overly soft or falling apart — it kept that firm, satisfying texture typical of pork loin. The breading stayed nicely attached to the meat rather than flaking off, and stayed crisp throughout. Despite being thick, the tonkatsu didn't feel too greasy, so it went down easily alongside the cold udon. The tonkatsu sauce was tangy and sweet and worked well with it, and the salt-and-wasabi combo felt like a nice, elevated way to eat it too.

Final verdict: who should eat at Kosi Seongsu Branch?

My favorite thing about Kosi Seongsu Branch was, hands down, the thick, springy, chewy Sanuki udon noodles. Add in the crisp shrimp and pumpkin tempura and the thick pork loin tonkatsu, and the set was hearty enough to fill up a full adult meal.

The dining room isn't huge, but with the counter and wall-side bar seats set up well, it felt like a comfortable option for eating alone when you're out in Seongsu. If you're after a tonkatsu spot in Seongsu, a place for chewy cold udon, or a tonkatsu restaurant near Seoul Forest, Kosi Seongsu Branch is worth keeping on the list.