Here’s a scene that baffles almost every visitor to Korea: it’s the hottest, most humid week of the year, and restaurants are packed with people sweating over bowls of boiling-hot chicken soup. Not cold noodles. Not ice cream. Steaming, ginseng-scented broth, eaten until the forehead drips. This is Boknal, Korea’s “dog days” food tradition, and the dish at its center is samgyetang. If the logic sounds backwards — hot soup to beat the heat? — that’s exactly the point. Here’s the idea behind it, and why you should try it if you’re in Korea this summer.
What is Boknal?
Boknal (복날), also called Sambok (삼복), is the three hottest days of the Korean summer, set by the lunar calendar. They fall about ten to twenty days apart: Chobok (초복), the start; Jungbok (중복), the midpoint; and Malbok (말복), the end. In 2026 they land on July 15, July 25, and August 14.
The word itself tells a story. The character “bok” (伏) shows a dog lying flat on the ground — the idea being that it’s so brutally hot even the animals just collapse and wait it out. That’s why English often calls this stretch the “dog days of summer.” Boknal began centuries ago as a farming tradition, a pause in the fields during the worst heat, when the season’s weather was read as an omen for the harvest.
Fight heat with heat: the logic of iyeol-chiyeol
So why hot soup? The tradition runs on a principle called iyeol-chiyeol (이열치열) — literally “fight heat with heat.” In traditional Korean medicine, when it’s blazing outside, your body’s core cools relative to the surface, weakening digestion and stamina. A hot, nourishing meal is thought to rebalance you from the inside, restoring the energy (gi, 기운) that summer drains away.
Modern science offers a parallel: eating something hot raises your core temperature and makes you sweat, and as that sweat evaporates it cools you down. Either way, there’s a real payoff at the end — that moment when you’ve sweated through the meal and suddenly feel light and revived. Koreans have a word for exactly that sensation: shiwonhada, a refreshed relief that, tellingly, is the same word used for something cool.
Samgyetang: the star of Boknal
The iconic Boknal dish is samgyetang (삼계탕), ginseng chicken soup. The name says what’s in it: sam (삼) is ginseng, gye (계) is chicken. A whole young chicken is stuffed with glutinous rice, garlic, jujube (red dates), and Korean ginseng, then simmered slowly in a milky, medicinal broth and served boiling hot in a stone bowl (ttukbaegi) that keeps it sizzling at the table.
The ginseng isn’t optional — it’s the whole point. The same dish without ginseng is called baeksuk, not samgyetang. Koreans consider samgyetang a boyangsik, a “stamina food,” part of a long tradition of treating food as medicine. It isn’t ancient in its current form: wealthy Koreans ate ginseng-powder chicken soup in the colonial era, it spread in the 1920s, and it only became an everyday dish for ordinary people after the 1960s. Today, famous samgyetang restaurants have lines out the door on Boknal, and supermarkets stack pre-made pouches for anyone too busy to simmer their own.
How Koreans eat it
Samgyetang arrives whole, and yes — you’re expected to work through the entire chicken yourself. It comes with kimchi (often kkakdugi, cubed radish) and a little dish of salt and pepper for seasoning the plain broth to taste; some restaurants add a small bottle of insam-ju (ginseng liquor). The classic finish is a slice of cold watermelon — the shock of cold after all that heat is part of the ritual.
Other Boknal foods, and a cooling-off custom
Samgyetang reigns, but it isn’t the only stamina food. Grilled eel (jangeo) is another popular pick, and red-bean porridge (patjuk) shows up for its cooling reputation. If a boiling bowl really isn’t your thing in July, Koreans also lean on cold dishes this season — naengmyeon (chilled buckwheat noodles) and kongguksu (cold soybean-broth noodles) — plus watermelon and patbingsu (shaved ice) to cool down.
And it isn’t only about food. A very old Boknal custom is dipping your feet in cool water to beat the heat — historically in mountain streams, and today many people do it right in the middle of the city, at spots like Cheonggyecheon.
If you’re in Korea this July or August, find a samgyetang restaurant on one of the three Boknal days, order the ginseng chicken soup, and eat it hot — sweat and all. Finish with cold watermelon, feel that wave of shiwonhada, and you’ll understand a piece of Korean summer that no thermometer can explain.