Ilwon-dong tonkatsu lunch comparing sirloin and tenderloin: Sioldon

Still a wait at 2pm on a weekday at Sioldon Ilwon Branch

Sioldon Ilwon Branch is a katsu restaurant at 12 Ilwon-ro 9-gil, 1F, Gangnam-gu, Seoul, on the Ilwon-dong food street. It's 5 minutes from the Samsung Seoul Hospital intersection and 8 minutes from Daecheong Station Exit 4, with 2 parking spots available right in front.

On my husband's rare weekday off, we got to enjoy a leisurely lunch date together for once. Since it was a weekday we had more time than usual, so while thinking about where to go for a good lunch, we decided on tonkatsu. We headed to Sioldon Ilwon Branch, an Ilwon-dong local favorite that takes its crispy tonkatsu seriously. Here's my review of the tonkatsu we enjoyed on our relaxed weekday lunch — a Samsung Hospital-area eatery, an Ilwon-dong favorite: Sioldon.

We arrived a bit late, around 2pm on a weekday. I figured lunchtime would be mostly over and we'd get a relaxed meal, but walking inside there were more people eating than I expected.

I guess it really is a place a lot of people come to in Ilwon-dong for good tonkatsu, haha.

The photo above is one I snapped of the dining room as we were leaving after our meal.

Partitioned tables and window seats for solo diners

Each table has a partition, giving a sense of separation from the next table, which made eating feel comfortable.

There are also nice window seats set up for solo diners, so the layout works well for eating alone too!

Kiosk ordering and 2,000 won off for takeout

At Sioldon Ilwon Branch you order at a kiosk. We took our time browsing the menu and picked the tonkatsu we wanted to eat.

There are value-for-money sets too, plus a ₩2,000 discount for takeout! Plenty of people were picking up takeout orders, and delivery riders kept coming in and out.

A popular spot with a wait, haha. There's even a thoughtful little touch: hair ties and disposable mouthwash on hand.

The menu was made up of various katsu sets and hot-pot (nabe) dishes. Apparently Sioldon is a tonkatsu-focused brand that started by researching the various breeds of Korean pigs and went on to study different aging methods and meat-curing techniques. Hearing that it was built through many rounds of testing and trial and error made me even more eager to try a proper katsu set, haha.

So among the katsu options, we ordered one tenderloin katsu set and one premium sirloin katsu set. I really wanted to taste tonkatsu done properly.

And sure enough, about 15 minutes later, the crispy katsu sets arrived.

Premium sirloin katsu set: the limited 72-hour cross-aged cut

The premium sirloin katsu set at Sioldon Ilwon Branch is made with domestic Korean pork that's cross-aged for 72 hours in-house, then cured with koji salt to bring out deep flavor from this special cut. It's sold in limited quantities, which made me even more curious.

The katsu came out neatly arranged, sliced long and thick — it looked delicious just to look at, haha.

Alongside the katsu came a cabbage salad with black sesame dressing. Rice, soup, and side dishes rounded out the set meal, making it a hearty, satisfying meal.

It also came with pink salt, fresh wasabi, mustard, and a special tonkatsu sauce to dip into as you like — nice to have so many options, hahaha.

You could see the fat and lean meat nicely mixed together. I tried the katsu plain first, without any sauce, curious what a 72-hour aged premium sirloin would taste like.

It had a chewy, springy texture... which paired really well with the crispy breading on the outside.

Next I tried it with tonkatsu sauce and fresh wasabi. The fresh wasabi had a sharp, pungent kick that was delicious.

Tenderloin katsu set: pink inside, soft all the way through

Next we tried the tenderloin katsu. Cutting into it, the cross-section had a faint pink tint, which surprised me at first — I wondered if it was undercooked, haha.

Apparently that color comes from the low-temperature aging process.

One bite in and, wow... it was seriously the most tender I've ever had. Along with the clean, mild flavor of tenderloin, it had a moist texture with not a single tough spot — it just melted in my mouth, hahaha.

It was so tender it was almost unbelievable, and I kept picking up piece after piece, hahaha.

Koji-salt curing and the peppery broth on the side

At Sioldon, they apparently use koji salt, a fermented salt, instead of regular salt. Koji salt keeps salt's natural saltiness but has lower sodium than regular salt, and it's said to be a natural seasoning that brings out the umami of meat. Maybe that's why the meat's curing tasted different from the tonkatsu I'm used to. Definitely a different kind of saltiness!! Even without dipping heavily in sauce, the meat itself had a subtle, savory depth.

The soup that came with the tonkatsu was also really good — I finished the whole thing. When your mouth starts to feel heavy from eating meat, a spoonful here and there really cleanses the palate.

It had chili flakes in it, so the spicy kick was really nice too.

Tenderloin or premium sirloin katsu: which should you order?

Our conclusion after trying both!! My husband's pick was the premium sirloin katsu — being limited quantity, plus he preferred the chewier texture of the meat — while mine was the tenderloin katsu. That soft, tender meat was just too delicious for me.

Same tonkatsu, but the premium sirloin has a chewy, savory charm while the tenderloin has a soft, juicy one — pick whichever suits your taste.

Sioldon Ilwon Branch, a Samsung Seoul Hospital-area favorite and an Ilwon-dong local pick, let us properly enjoy both the crispy breading and the natural flavor of the meat. If you're ever craving proper tonkatsu in Ilwon-dong, pick whichever katsu set suits your mood from their range and enjoy a great meal. I'd recommend Sioldon Ilwon Branch as a tonkatsu spot!! Great for lunch, great for dinner, and perfect for solo dining too!