The Jin state, existing between the 4th to 2nd centuries BCE, was a confederation of statelets in the southern part of the Korean peninsula, neighboring the Gojoseon kingdom to the north.^[23] Its capital was located somewhere south of the Han River. While the exact organizational structure of Jin as a formal political entity remains uncertain, it appears to have been a federation of smaller states, similar to the later Samhan confederacies. Despite the uncertainties, Jin's interactions with Wiman Joseon and its attempts to establish diplomatic ties with the Western Han dynasty indicate some degree of stable central authority. Notably, after Wiman usurped his throne, King Jun of Gojoseon is said to have sought refuge in Jin. Moreover, some scholars believe that the Chinese references to Gaeguk or Gaemaguk could pertain to Jin.^[24]

The downfall of Jin is a topic of debate among historians.^[25] Some records suggest that it evolved into the Jinhan confederacy, while others argue that it branched out to form the broader Samhan, encompassing Mahan, Jinhan, and Byeonhan. Archeological findings related to Jin have been predominantly discovered in areas that later became part of Mahan. The Chinese historical text, Records of the Three Kingdoms, asserts that Jinhan was the direct successor of Jin. In contrast, the Book of the Later Han posits that Mahan, Jinhan, and Byeonhan, along with 78 other tribes, all originated from the Jin state.^[26]

Despite its dissolution, the legacy of Jin persisted in the subsequent eras. The name "Jin" continued to resonate in the Jinhan confederacy and the term "Byeonjin," an alternate name for Byeonhan. Additionally, for a certain period, the leader of Mahan adopted the title "Jin king," symbolizing a nominal supremacy over the tribes of Samhan.