While gejang was originally used to refer to crabs marinated in soy sauce, it is now also called ganjang-gejang (간장게장) to differentiate it from yangnyeom-gejang (양념게장).

Its origins appear to come from the Chungcheong and Jeolla provinces, which both have long-standing traditions of mixing raw fish or dried pollock with a spicy red pepper flake or gochujang sauce.

[5] According to Korean traditional medicine, crabs possess a 'cold nature' that can cool one's body temperature, and so gejang is believed to be good for driving away the spring fever.

According to Sallim gyeongje which is written around the end of the 17th century, making gejang is referred to as "johaebeop" (조해법, 糟蟹法), which means "a way of marinating crabs in sediments of liquor".

With this method, crabs are marinated in a mixture of jaegang (재강, sediments of liquor), salt, and an alcoholic beverage.

The most delicious blue crabs are considered to be those caught from December to June for females, and from July to October for males, although the timing can vary by species.

North Korean gejang is not cooked, so it is best to use richly flavored brewed soy sauce to enhance its taste and aroma.

The Japanese interest in ganjang gejang stems from the similarities in food culture, such as the use of soy sauce, rice, and seafood.

Additionally, it was an unfamiliar type of food in Japan, and after the “Winter Sonata” boom, Japanese tourists visiting Korea often included ganjang gejang in their dining experiences.

A variation involves adding minced beef while the sauce is poured over the crabs, endowing the gejang with more spices.

[1] In present times, some people may choose to add lemon, chili pepper, or traditional medicine when making gejang to remove its fishy smell and increase its rich flavor.

Among varieties, beoltteok gejang (벌떡게장) is a local specialty of the Jeolla Province and is made with live Charybdis, which are called either beoltteokge (벌떡게) or minkkotge (민꽃게) in Korean.

[15] The crab has a hard carapace with a reddish-brown color and is found in the seawater of Korea, according to Jasaneobo (자산어보 "Fishes of the Huksan Island"),[16] the first Korean fisheries science book written by scholar Jeong Yak-jeon (정약전) in 1814.

However, beoltteok gejang can not be preserved for a long time, so it is said that the name reflects the fact; beotteok means "quickly" or "immediately" in Korean.

After being cleaned, the live crabs are chopped into several pieces and a mixture of ganjang, containing sliced scallions, garlic, ginger, chili pepper powder, sesame seeds, and salt is poured over them.

In Jeju Island, gejang is called gingijeot (깅이젓) and is made on the fifteenth of every March in the lunar calendar at low tide.

It is made with chamge (Chinese mitten crab) which generally live in the rivers of Korea that flow to the Yellow Sea.

[citation needed] As records on chamge can be found in several historical documents regarding fisheries and cuisine such as Jasaneobo, Gyuhap chongseo (Women's Encyclopedia[8]), and the chapter Jeoneoji (전어지) of Imwon gyeongjeji (임원경제지), it is clear that the dish has been a long-standing Korean delicacy.

[18] Chamgejang is also widely eaten in the Gyeongsang Province, and is prepared at every house during autumn to make a banchan (small side dish) for the next summer.