Coastal Korea; gejang appears in documents from the Three Kingdoms period. The ganjang gejang tradition is strongest in the southwestern coastal regions (Jeolla province) where blue crab populations are most abundant
Gejang (게장) is raw blue swimming crab marinated in either ganjang (간장게장, soy gejang) or gochugaru-yangnyeom (양념게장, spiced gejang), a tradition sometimes called 'rice thief' (밥도둑) for its appetite-stimulating power. The raw crab — specifically Portunus trituberculatus (blue swimming crab, 꽃게) — is not cooked but 'cold-processed' by the salt content of the marinade over 3–12 hours for yangnyeom gejang, or 3–7 days for soy gejang. The result is silky, almost liquid crab meat that slides from the shell and is eaten with rice. The crab roe (내장, naejang) in the shell is the prize: a creamy, intensely savoury paste.
Ganjang gejang served at room temperature (the roe semi-softened) with hot steamed rice is one of the most intensely satisfying Korean meals. The soy's salt draws moisture from the crab, which dilutes into the marinade, which you then pour over rice — the dish continuously replenishes itself.
{"Female crabs with roe (암게, amge) are preferred for ganjang gejang; the roe becomes a silky paste in the soy marinade","For ganjang gejang: boil the soy sauce with aromatics, cool completely, pour over cleaned raw crab; repeat 2–3 times over 3 days — each repetition concentrates the marinade and re-penetrates the crab","Crab freshness is the where the dish lives or dies — gejang made from crab dead more than 2 hours carries food safety risk (Vibrio) and flavour loss; live or just-killed crab only","The soy marinade should be sweet-savoury with garlic, ginger, chilli, and a small amount of Asian pear or apple — the sugar in fruit balances the soy's salt and helps preserve the raw crab"}
The traditional method of eating ganjang gejang: hold the crab body over the rice bowl, use chopsticks to scoop the roe paste from the shell directly onto rice, then mix. The rice absorbs the soy-crab mixture and takes on a silky, savoury quality that explains why gejang is called 'rice thief' — it makes eating plain rice irresistible. Yeosu (여수) is famous for high-quality ganjang gejang made with local Yellow Sea blue crab.
{"Using frozen crab — the cell structure is disrupted by freezing, producing watery, loose crab meat that doesn't hold the soy marinade; only live or fresh-killed crab produces the characteristic silky texture","Under-marinating yangnyeom gejang — less than 3 hours produces a half-raw, half-marinated product; 6–12 hours allows the gochugaru and salt to fully penetrate the crab flesh"}