Seiwa Genji 源
The emblem (mon) of the Minamoto clan, of which the Seiwa Genji were a branch
Parent house	Minamoto clan
Founder	Sons/grandsons of Emperor Seiwa, e.g. Minamoto no Tsunemoto (源 経基)
Final ruler	Minamoto no Sanetomo
Founding year	10th century
Cadet branches	Ashikaga clan Hatakeyama clan Hosokawa clan Imagawa clan Mori Nanbu clan Nitta clan Matsudaira clan Tokugawa clan Ogasawara clan Ōta clan Satake clan Satomi clan Shiba clan Takeda clan Toki clan others

The Seiwa Genji (清和源氏) is a line of the Japanese Minamoto clan that is descended from Emperor Seiwa, which is the most successful and powerful line of the clan. Many of the most famous Minamoto members, including Minamoto no Yoshitsune, Minamoto no Yoritomo, the founder of the Kamakura shogunate; and Ashikaga Takauji, the founder of the Ashikaga shogunate, belonged to this line. Tokugawa Ieyasu (1543–1616), founder of the Tokugawa shogunate, also claimed descent from this lineage. The family is named after Emperor Seiwa, whose four sons and twelve grandsons founded the Seiwa Genji. Emperor Seiwa was father of Imperial Prince Sadazumi (貞純親王 Sadazumi Shinnō) (873–916), who was in turn the father of Minamoto no Tsunemoto (源経基) (894–961), one of the founders of the Seiwa Genji, from whom most Seiwa Genji members are descended. Many samurai families belong to this line and used "Minamoto" clan name in official records, including the Ashikaga clan, Hatakeyama clan, Hosokawa clan, Imagawa clan, Mori, Nanbu clan, Nitta clan, Ogasawara clan, Ōta clan, Satake clan, Satomi clan, Shiba clan, Takeda clan, Toki clan, Tsuchiya clan, among others. The Shimazu clan and Tokugawa clan also claimed to belong to this line.

A group of Shinto shrines connected closely with the clan is known as the Three Genji Shrines (源氏三神社 Genji San Jinja).

Family tree

The following family trees are a non-exhaustive listing of the Seiwa Genji and the clans that branched from the family.

Legend: Solid lines represent blood relationship; dashed lines represent adoptions. An asterisk indicates a monk (who would not have been allowed to retain the Minamoto name).

Emperor Seiwa's first five princes

Prince Sadazumi's descendants

Emperor Seiwa's other princes

Settsu Genji

Yamato Genji

Kawachi Genji

Yoshimitsu's descendants

Mitsumasa's descendants

Mitsuyoshi's descendants