Koihime Musou Girls and Korean Clans which are NOT SAFE to PRONOUNCE, Part IV: OH! (오/吳)
Oh (오/吳), also romanized O is a Korean family name. The name originates from the ancient state of Wu in present-day Jiangsu Province, Mainland China. It is the sixth name listed in the Song Dynasty classic Hundred Family Surnames, 10th most common surname in China and 12th most common surname in Korean Republic.
In the 13th century BCE, the state of Zhou (which will later become the Zhou Dynasty) was ruled by King Tai of Zhou. His surname was originally Ji (姬). He had three sons: Taibo, Zhongyong, and Jili. King Tai of Zhou favored the youngest son, Jili to inherit the reins of power, therefore Taibo and his brother Zhongyong voluntarily left Zhou with a group of followers and headed southeast where they established the state of Wu. Taibo and Zhongyong's descendants eventually adopted Wu (吳) as their surname. The state of Wu, which later claimed to be a kingdom of its own, was best known for its military prowess as Sun Tzu, the author of the famed book The Art of War, was the country's general serving under King Helü of Wu. King Helu is considered to be one of the Five Hegemons of China during the Spring and Autumn period.
Taibo and Zhongyong's youngest brother Jili stayed to rule the Zhou state and was the grandfather of Wu Wang (King Wu of Zhou) who started the Zhou Dynasty after successfully overthrowing the Shang Dynasty. The descendants of Wu Wang eventually changed their surname from Ji (姬) to Zhou (周) during the Qin Dynasty to commemorate the merits and virtues of their ancestors.
There were two Chinese characters for the Oh surname, but by the late Goryeo period (14th century CE), one of them had disappeared. Some records indicate that there are as many as 210 different clans for the remaining character, but only sixteen can be positively documented. All sixteen of these clans originate from the same ancestor, Oh Cheom (오첨/吳瞻), who migrated to Korea from China during the first reigning year of King Jijeung-Maripgan, 22nd King of Silla (500CE).
Based on the 2015 Korean Republic Census - provided by Statistics Korea (통계청/統計廳/Tonggyecheong/KOSTAT), there are 763,281 people who bear the surname of Oh. The most dominant designated clan for this surname is Haeju Lineage, where this lineage consists of 462,704 people.
The Haeju Oh Clan (해주 오씨/海州吳氏) was founded by Oh In-yoo (오인유/吳仁裕) and Oh Hyeon-bo (오현보/吳賢輔). The ancestral seat is located at Haeju City, Southern Hwanghae Province in the present-day North Korea (DPRK). This clan is divided into two branches which are The Capital Branch (경파/京派/Gyeongpa) and The Rural Branch (향파/鄕派/Hyangpa). The Capital Branch of Haeju Oh Clan was founded by Oh In-yoo, a scholar from Chinese Song Dynasty who migrated to Goryeo in 984CE - the third Reigning Year of King Seongjong Wang Chi, 6th King of Goryeo Dynasty. On the other hand, The Rural Branch of Haeju Oh Clan was founded by Oh Hyeon-bo, Lord of Haeju (해주군/海州君) - 24th Generation-Descendant of Oh Cheom, the progenitor of Oh Clan in Korea.