Korean connection to Manchurians
People in Manchuria was called in many different names, Jurchen, Dongyi, Sukshin, Yupru, Malgal, etc. The ancestors of Manchus are people who lived in current North Korea and Manchurian area. Both Koreans and Manchus explain their origin from Baekdu Mountain (Chanbai, 长白山, Golmin Šanggiyan Alin, 백두산, 白頭山), and this mountain is regarded as a sacred place to both ethnics. Jurchens were one of the tribes of Goguryeo, Balhae, and Gojoseon.
Hambo who was from Silla (新羅) moved to northern Korean penninsular, and originated Jin dynasty (Aisin Gurun, 金朝, 금나라) unifying Manchuria. When they restored Jin dynasty in 1616 (later changed to Qing dynasty) , they coined the term "Manchu" referring to themselves. Qing government published a history book ("The origin of Manchu" [1 ] ) about their origin defining Manchu tribes, and all Korean tribes were included as Manchu. In the book, they explained their origin from Silla (新羅).
Genetic analysis shows that Manchus are genetically closest to Koreans among Koreans, Mongols, Japanese and Chinese . Manchuria was homeland to ancient Koreans for Gojoseon, Goguryeo, and Balhae kingdoms. Korean gene significantly contributed to Manchu gene pool.
Gojoseon connection to Jurchens
According to the foundation story of Gojoseon, three tribes are related to Gojoseon people. Hwanung tribe, the bear tribe, and the tiger tribe. Some historians believe that Jurchens are one of the tribes. Manchu Tungusic people have bear totemism  and Northeast Korea to East Manchuria is the traditional habitant of Tigers. One of theories explains that the origin of the name Jurchen was from Sushen (肅愼, Suksin, 숙신), and the terms of Jurchen, Sushen, Joseon are from the same origin with differentiated pronunciation .
Jin dynasty had a national ritual every October for their ancestor Gaecheon-hongseongje (開天弘聖帝, 개천홍성제) in Baekdu Mountain (长白山, 백두산, 白頭山). Gaecheon-hongseongje means "The sacrit person opening the heaven with spirit Hong (弘, great and broad)". The founder of Gojoseon is called Dangun(檀君) who originated Koreans from the Baekdu Mountain, and Koreans have a ritual every October too. The day of the foundation is called Gaecheon-jeol (開天節) which is a national holiday of Korea. The main idealogy of Dangun was Hong-yik-Ingan (弘益人間) meaning "great and broad benefits to people". Manchu Qing dynasty recorded him as "開天宏聖帝" in the origin of Manchu (滿洲源流考). Both "宏" and "弘" are "Hong".
•冊長白山之神為開天弘聖帝 (in chapter 10, History of Jin (金史) )
•明昌四年十月 ... 行仗五百人，複冊為開天弘聖帝。(in chapter 35, History of Jin (金史) )
Goguryeo connection to Jurchens
Jurchen was part of Goguryeo as king Gwangaeto conquered Sushen (肅愼, 숙신) in 398. As Chinese Tang invaded Goguryeo, Jurchens as people of Goguryeo fought against Tang army.
Silla(新羅) connection to Jurchens
After Silla destroyed Goguryeo and expanded territory further north, some people of Silla moved to north which
1115-1234 Jin dynasty (Jurchen Altaic people): the capital was Beijing
was old Goguryeo's area. After the collapse of Silla, some people of Silla escaped to north to Jurchen's area (current north Korea). They unified Manchuria establishing Jin dynasty.
The originator of Jin dynasty was a Silla person. His name was Hambo. The emperor of Jin dynasty was called a Silla person by Song Chinese who visited Jin in 1120s. Some history books say that the Jurchen King was a Silla person, others say that the originator of Jin was first from Goryeo. It is because Silla was replaced by Goryeo. However, Chinese, Mongol, Korean, and Manchu history records are consistent impling that Jurchen kings are originally from Silla.
•"The name of the originator of Jin(金) is Hambo(函普). When he came first from Goryeo(高麗), his age was 60"
◦"金之始祖諱函普，初從高麗來，年已六十餘矣" (in 1st chapter of the history of Jin(金史) )
Not only the originator of Jin, but also Agolta (阿骨打), the founder of Jin dynasty, was called originally a person from Silla
•"Agolta (阿骨打) of the Jurchens declared to be the Emperor, ... He was originally a person of Silla (新羅人)"
◦女真阿骨打稱帝，姓王名做旻，本新羅人，號完顏氏 (in 3 宣和遺事 (大宋宣和遺事)) 
•Jurchen Agolta named the state Great Jin (大金) (... He is originally a person of Silla).
There are lots of history records showing that the originator of Jin dynasty was a Silla person (or from Goryeo)
•The originator of Wonan family (Jin's royal family) is a person of Silla
◦完顏之始祖指蒲者，新羅人 (in 大宋遗民)
•The name of the originator of Jin is Hambo. He came first from Goryeo (髙丽)
◦金之始祖諱函普初從高麗來 ( in 大金國誌 written by Song Chinese)
•The originator of Jin, Hambo was first from Goyreo.
◦金之始祖諱哈富(舊作函普)初從髙麗來 (in 三朝北盟會編 written by Song Chinese)
Mongol and Korean records are consistent showing that the originator and the king of Jin dynasty are Silla persons. Goryeo claimed that Jin dyansty was originally inside Goryeo and they were people of Goryeo, and Goryeo was the mother country of Jin dynasty
•"People of Jin was originally Pyungjoo people in our country Goyreo. Goryeo was a mother country of Jin."
◦"金則本我國平州之人, 稱我爲父母之國, 尹灌築九城之地, 以先春嶺爲界, 終金之世, 兵不相加。"(高麗史 written by Korean dynasty)
•"The king of Jurchens is originally a Silla person"
◦"其初酋長本新羅人" (in 金志 written by Mongols in Yuan dynasty)
Until when did the royal family of Jin dynasty know that they were from Silla? When Jurchens visited Goryeo, they said their country was originated from Goryeo.
•" My ancestors (我祖宗) originated from your High country (大邦: Goryeo)."
◦"我祖宗出自大邦" (from 高麗史13卷-世家13-睿宗1109, written by Korean in Goryeo)
When Jin dynasty invaded Song China, two Chinese emperors were captured as hostages in 1127. Southern Song Chinese visited Jin dynasty to negotiate with Jin to find a way to get their emperors back in 1129. They stayed in Jin for 10 years and wrote all information about Jurchens. They wrote that the leader of Jurchens was a person of Silla . It shows that the royal family of Jurchen was called people of Silla even after Jin dynasty was founded. This record is highly credible because it was written during Jin period.
•The king of the Jurchens is a person of Silla.
◦女真酋長乃新羅人 (in 松漠記聞 (洪皓, 宋), 1129, written by Song Chinese) [10 ]
Who is exactly HamBo(函普 ), the originator of Jin(金) dynasty from Korea?
appears in different names in references. "Kam Bok(龕福)" in 松漠記聞 can be closer to the original
name because it was written during Jin period and it is the earliest record.
•Ham Bo (函普, 함보) in History of Jin(金史) in 1300s 
•Hab Bu (哈富, 합부) in The Origin of Manchu (滿洲源流考) in 1777 
•Kam Bok (龕福, 감복) in 松漠記聞 in 1129 (洪皓, 宋)) [10 ]
There are several historic records with different names about him in Korea. It is generally accepted by historians that he is a prince of the last king of Silla, GyeongSoon . When Silla was replaced to Goyreo, his prince joined movement to recover Silla. The name of the prince is Kim Bu (김부, 金富) in Hyangchal (the writing system used in Silla period) [13 ].
•Kim Bu (金富, 김부), the name of the last prince of Silla in Hyangchal
The prince and his followers staged in Inje , Gangwon province for the movement to restore Silla.
Hamgyong NamDo, Korea
They built Little Silla (신라소국) there. After Goyreo's attack, they moved to a Jurchen's area (YoungHeung, Hamgyeong-NamDo , North Korea) [11 ] [12 ] [7 ], and he became the originator of Jin(金, Kim) dynasty. It is believed that he had a big number of followers with military trained for battles with Goryeo, and it made possible for them to lead Jurchen tribes in the early settlement. Minority theory explains that Hambo was another prince of the last king of Silla, or possibly the last king himself.
•Kim Boon (金奮 김분), another prince of Silla
•Kim Bu (金傅, 김부) , the name of the last king of Silla
Hamgyong NamDo, Korea
Korean connection to Manchus of Qing dynasty
Manchu Qing dynasty(1636-1912) is the successor of Jurchen's Jin dynasty (1115-1234) .
1616-1911 Qing dyansty (Manchu Altaic people): the capital was Beijing
Jurchens rebuilt Later Jin dynasty in 1616. They changed the country name to Qing (1636), and conquered China (1644), Mongolia (1697), Taiwan (1683), Tibet(1750), and Uyguru(1759). The royal family of Qing believed that they were descendents of Jin's royal family.
Manchu people in Qing dynasty also knew that the originator of Jin dynasty was from Goryeo (or Silla). Qing government published their own history book, "The origin of Manchu (滿洲源流考) " in 1777. They explained that the originator of Jin dynasty was first from Goryeo in the the book of History of Jin, but it is because the words Silla and Goryeo were used referring to Korea. They explained that Hambo was actually from Silla(新羅). Also, they wrote that the origin of the country name Jin (金) was from the surname of kings of Silla(新羅). Kim (金) is the most popular surname in Korea and it was from the surname of Kings of Silla. In this book they explained their origin from Silla.
•According to the History of Jin, ... the name of the originator of Jin is Hambo. He came first from Goryeo (髙丽)
◦金史世纪, ... 金之始祖讳哈富(旧作函普)初从髙丽来 (in Chapter 7, The Origin of Manchu (滿洲源流考)  )
•Thus, the originator of Wanyan Jin (金) came from Silla.
◦完顔金始祖自新羅來居完顔部因以爲氏 (in The Origin of Manchu (滿洲源流考)  )
•The name of Jin(金) dynasty came from the surname of kings of Silla(新羅)
◦新罗王金姓则金之逺派 (in The Origin of Manchu )
•Silla came to Wannan family. Silla kings' surname 金(Kim in Korean) inherited ten generations. So, Jin(金) came from Silla. There is no doubt that it became the country name.
◦本自新羅來姓完顔氏 新羅王金姓 相傳數十世則金之自新羅來 無疑建國之名 "(in The Origin of Manchu )
Also, Qing emperors' surname was "愛新覺羅". Interestingly, it can be read as "love Silla (愛 新羅) and remember Silla (覺 新羅)". The surname "愛新覺羅" means gold(金) clan in Manchu pronunciation (Aisin Gioro). The surname Kim(金) of Silla kings means gold too. After the end of Qing dynasty, the descendents of royal family changed their surname to Jin (金, Kim).
The Manchu royal family Aishin Giro (愛新覺羅) clan were people who lived
North Hangyong, Korea
in Odoli Castle which is in current Hoeryong (회령), North Hamgyong in North Korea where was part of Joseon dynasty since 14th century [15 ]. They were a vassal tribe to Joseon dynasty, and they treated Joseon as a mother country. The founder of Qing dynasty, Nurhachi, was born in Joseon Korea. He called Joseon dynasty "mother country" in the letter to Joseon showing willingness to help Joseon at the invasion of Japan in 16th century. The foundation story of Qing dynasty explains the birth place of Nurhachi, who was the founder of Qing, as the east of Baekdu Mountains which is current North Korea [16 ].
•"There was a lake called Bulhūri at the foot of Bukūri Mountain, located to the east of the Baekdu Mountains. When three angels bathed in that lake, a magpie left a fruit on the youngest angel Fekulen's clothes. She ate the fruit and became pregnant. She mothered Bukūri Yongšon, the founder of Aisin Gioro. He was later welcomed by the people as the Beile. He settled at Odoli Castle on the Omohoi Plain and became the founder of the Manchu State."
Qing government announced the definition of Manchu and prohibited the term 'Jurchen' referring to them. The half of Manchu tribes were Korean tribes, and all Korean tribes were included. (Goguryeo tribe was included by Balhae)
•Definition of Manchu from "The origin of Manchu (滿洲源流考)" 
Manchu Tribe 1: Suksin (肅愼), Buyeo(夫余, Korean)
Manchu Tribe 2: Yilou (挹娄, Ainu), Samhan(三韩, Korean), and Mulgil (勿吉)
Manchu Tribe 3: Baekje(百济, Korean)
Manchu Tribe 4: Silla(新羅, Korean)
Manchu Tribe 5: Malgal(靺鞨)
Manchu Tribe 6: Balhae(渤海, Korean)
Manchu Tribe 7: Wanan (完颜, Korean royal family), and GeonJu (建州)
How long did Silla identity remain?
It is not clear how long Silla identity remained in the royal family of Jin dynasty. However, there are several clues implying their identity. His brother moved with him, and in commonsense, their family and followers must have moved together. It is not clear how many people moved from Silla.
If Ham Bo ( 函普) is Kim Bu (金富) who was the last Silla prince and the leader of Silla Recovery Movement, a lot of followers must have moved with him to the Jurchens area. They must have married women among their group in the early period. Traditionally, royal family of Silla married only among their royal family members. Marriage of brother and sister was common to maintain a pure blood line. People of mixed heritage was excluded in the central pure royal family [14 ]. So, their descendants after Hambo can be 1/2 Korean, 3/4 Korean, 7/8 Korean, 15/16 Korean, ... 255/256 Korean in Aguda. This part is not clear, so we should not assume anything without clear evidence.
However, it is clear that they had identity as people from Silla at least until 12th century after they founded Jin dynasty and moved capital to Beijing. Southern Song Chinese visited them wrote them as people of Silla in 1129.
" The king of the Jurchens is a person of Silla."
•女真酋長乃新羅人 (in 松漠記聞 (洪皓, 宋), 1129, written by Song Chinese) [10 ]
After Jin included Balhae, Jin royal family marred women from Balhae. Jin dynasty's kings were from Silla descendants and queens from people of Balhae.
After they built Qing dynasty, they used the royal surname "Aishin Giro (愛新覺羅)" meaning Kim (金, Jin) family, and published the Origin of Manchu (1777) explaining their origin from Silla, correcting the records of other history books explaining from Goyreo. They included all Korean tribes in the concept of Manchu. It implies that they considered Koreans as the same ethnic group sharing the common origin from Silla during Qing dynasty.
 Qing governement, "The origin of Manchu(滿洲源流考)", 1777, http://zh.wikisource.org/wiki/%E6%BB%BF ... 1%E8%80%83
 大宋宣和遺事, http://open-lit.com/showlit.php?gbid=347&cid=1
 the history of Jin(金史), http://zh.wikisource.org/wiki/%E9%87%91 ... %E5%8D%B71
 Sin Chaeho, "Joseon Sanggosa", 1931, http://en.wikipedia.org/wiki/Joseon_Sanggosa
 Toru Katoh, et. al., "Genetic features of Mongolian ethnic groups revealed by Y-chromosomal analysis", **Gene**, Volume 346, 14 February 2005, Pages 63-70. web link
 Wontack Hong, "How Did the Rulers of the Jin and Qing Dynasties Trace Their Ancestors? The Manchu Origins", EAST ASIAN HISTORY: A KOREAN PERSPECTIVE Vol. 1. No. 2. 2005. 1. 1. http://www.upkorea.net/news/photo/4908-2-4504.pdf
 "Hanpu", wikipedia.org. http://en.wikipedia.org/wiki/Hanpu
 Juha Janhunen, "Tracing Bear totemism in Northeast Asia", http://src-h.slav.hokudai.ac.jp/publict ... nhunen.pdf
 "The founder of Jin dynasty, Agolta was a descendent of Silla", History special, KBS, 2009,http://www.kbs.co.kr/1tv/sisa/historysp ... 30885.html
 洪皓(Song Chinese), "The king of Jurchens is a person of Silla (女真酋長乃新羅)"', in '松漠記聞', 1129, http://zh.wikisource.org/wiki/松漠紀聞
 "마의태자(麻衣太子)", http://ko.wikipedia.org/wiki/마의태자
 "함보(函普)", http://ko.wikipedia.org/wiki/함보
 History special, KBS, http://www.youtube.com/watch?v=bQ4AAYxg0-U
 Bone rank system, http://en.wikipedia.org/wiki/Bone_rank_system
 Manchu - origins, http://www.experiencefestival.com/a/Man ... 1743269[16
] "Nurhachi, The Qing, and the Taiping " in Asian millenarianism: an interdisciplinary study of the Taiping, pp37-38, 2007