Kah (가/賈), sometimes romanized Gah, Ga or Ka is an uncommon Korean Surname which means 'merchant' in Sino-Korean Language, similar to Chinese Jia. Jia/Kah is the 45th most common surname in Mainland China and 113th most common surname in Korean Peninsula. The Jias are the descendants of ancient emperor Huang Di.
During Emperor Zhoukang's reign, he awarded Zi Gong Ming (son of Tang Shuyu) as the duke of Jia. Zi Gongming also known as Jia Bo, is commonly regarded as the forefather of the Jia family. During Chun Qiu, the Jia kingdom was eliminated by Jin. The duke of Jin thus awarded the kingdom to his uncle, Wu Shegu. Wu Shegu is also known as Jia Ji or Jia Ta. The duke of Jin wanted to make Jia Ji his commander in chief and make Zhao Xun his deputy. Yang Chufu (a high ranking judge), due to his connection with Zhao, convinced the duke of Jin to make Zhao the chief commander, and Jia his deputy. Because of this Jia hated Yang deeply.
After the duke of Jia died, Jia suggested to appoint Gong Zi Le (brother of the deceased duke of Jin as the new duke and sent for him. Zhao, on the other hand wanted to appoint Gong Ziyong (another brother) as the new duke. Zhao ordered the assassination of Gong Zi Le, and in revenge, Jia ordered the assassination of Yang Chufu. Zhao caught and executed the assassin, and exiled Jia. His descendants began to bear the last name Jia.
Back in Korea, there are 9,090 people in 2,824 families who bear the surname of Kah, based on the 2000 Korean Republic Census - provided by Statistics Korea (통계청/統計廳/Tonggyecheong/KOSTAT). The Soju Lineage, a clan which is originated from Suzhou City, Jiangsu Province, PROC is the most dominant among Kah Clan where this lineage consists of 9,025 people in 2,812 families.
Soju Kah Clan or Suzhou Jia Clan (소주 가씨/蘇州賈氏) was founded by Kah Yoo-yak or Jia Weiyao (가유약/賈維鑰) an army officer from Chinese Ming Dynasty who helped Joseon Dynasty against Japanese Invasion Forces during Jeongyu Incursion - the second round of Japanese Imjin Invasion. This clan is also known as Taean Kah Clan (태안 가씨/泰安賈氏), based on their clan-based village in Taean County, Southern Chungcheong Province, ROK.