Where Sejak sits

Under Korean law, Sejak is green tea plucked between 8 and 10 days after Gogu (곡우, around 20 April), using one bud and three leaves (1심3엽). The ordinance’s own words: “절기상 곡우 이후 8일에서 10일 사이에 채취한 차나무 잎으로 1심3엽을 사용한 것.” Gogu is astronomical rather than a fixed calendar date, so the window shifts by about a day from year to year — and it is narrower than most English descriptions suggest.

Note the fifth row. Most English-language accounts list four grades; the ordinance defines five, with 곡우 (Gogu) sitting between Ujeon and Sejak.

The hanja varies in circulation: 細雀 with the “sparrow” character, and 細茶 with the “tea” character. The bird reading comes from 작설 雀舌, “sparrow’s tongue,” an old description of the leaf shape. Both forms are in use in Korea.

The same annex also governs how the picking date is written: year, month and the early, middle or late third of the month (년 월 상·중·하순). Where leaves picked at different times are blended, the latest picking date is the one that must be shown — useful to know when you are reading a spec sheet. Where leaves from several 시·군·구 are blended, the label may carry the 시·도 name or simply “국내산” (domestic).

Law, county and producer: three usages you will meet

This is worth knowing because it explains the inconsistencies you will meet across suppliers. The accurate picture has three layers, and they are all still in circulation.

1. A trade convention. The names began as trade usage anchored to the twenty-four solar terms, long before any statute existed. That is where they come from, and it is why they track Gogu and Ipha rather than calendar dates.

2. An ordinance labelling standard. Since the Tea Industry Act, the five labels are defined for green tea by picking window and leaf count, as set out above. This is the layer to lead with, because it is the only one that is written down and checkable.

3. Producer and regional usage, which has not fully converged. Hadong County’s own published definitions differ from the ordinance: it describes Sejak as running from Gogu to before Ipha — roughly a fortnight, rather than the ordinance’s three-day window — and Daejak as a late-May pluck rather than a June-onward one. Osulloc, Korea’s largest producer, uses the words differently again: Ujeon, Gogu-cha and Ipha-cha as the date axis, with Sejak, Jungjak and Daejak as a size classification.

So a buyer can meet all three usages in the same market, on the same shelf. The divergence between the ordinance, a county and a major producer is real and checkable — and it is the reason the practical answer is always the same: ask for the pluck date and the leaf standard alongside the grade name. Quote the ordinance for what the word means; quote the date for what you are actually buying.

Sejak is not the Korean sencha

This comparison comes up constantly and it confuses two different kinds of category.

• Sencha is a processing style — Japanese green tea that is steamed to fix the leaf.
• Sejak is a plucking standard — it says when the leaf was picked and how much of it was taken with the bud, not how it was made.

Most Korean green tea, and Hadong’s in particular, is pan-fired (덮음) in a cauldron rather than steamed. That is the real divergence in the cup: pan-firing pushes the tea toward roasted, nutty and rounded notes, where steaming holds the marine, vegetal register that defines sencha. Two teas can share a plucking window and taste nothing alike.

Why Sejak is usually the right grade for a business

Korea is a small origin — 2,624 hectares producing 4,185 tonnes of fresh leaf in 2023, roughly 800 tonnes finished. Ujeon is a slice of that taken in a window a few days wide, which is why it does not exist in the volumes a hotel group or a distributor needs, at any price.

Sejak comes later in the flush, with enough leaf development to hold a consistent profile across a season, and it still carries spring character. For a menu that has to taste the same in September as it did in May, that consistency is worth more than a scarcer grade. In practice the trade also uses the name across a wider window than the ordinance draws — which is precisely why the pluck date belongs on the spec sheet next to the grade name.

On price, one Boseong producer’s organic line showed roughly an eightfold spread per gram between Daejak and Ujeon in the same season, with Sejak sitting in the upper middle of that range.

Cultivars, and a measured difference

Korea has bred its own tea cultivars — twenty-two registered with the Korea Seed & Variety Service by 2023. Two of them, Bohyang (보향) and Chamnok (참녹), were developed in Jeollanam-do and measured by the Rural Development Administration with Chonnam National University against the Japanese cultivar Yabukita: catechin content higher by 22.9% and 23.4% respectively, and cellular antioxidant effect higher by 16.2% and 18.2%.

Worth knowing because Yabukita is also planted in Korea, particularly on Jeju. When a supplier can name the cultivar, you learn something; when they cannot, that is information too.

Two questions worth asking

• Pan-fired or steamed? It changes the cup more than the grade name does.
• Which cultivar, and where? Jaerae-jong seed-grown tea from Hadong, a named Korean cultivar, and Japanese cultivar acreage on Jeju all sit under “Korean tea.”

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