Seiwa Genji in the context of "Hatakeyama clan"

Minamoto (源; Japanese pronunciation: [mʲi.na.mo.to]) was a noble surname bestowed by the Emperors of Japan upon members of the imperial family who were excluded from the line of succession and demoted into the ranks of the nobility since 814. Several noble lines were bestowed the surname, the most notable of which was the Seiwa Genji, whose descendants established the Kamakura and Ashikaga shogunates following the Heian era. The Minamoto was one of the four great clans that dominated Japanese politics during the Heian period in Japanese history—the other three were the Fujiwara, the Taira, and the Tachibana.

In the late Heian period, Minamoto rivalry with the Taira culminated in the Genpei War (1180–1185 AD). The Minamoto emerged victorious and established Japan's first shogunate in Kamakura under Minamoto no Yoritomo, who appointed himself as shōgun in 1192, ushering in the Kamakura period (1192–1333 AD) of Japanese history. The name "Genpei" comes from alternate readings of the kanji "Minamoto" (源 Gen) and "Taira" (平 Hei).

The Hosokawa clan (細川氏, Hosokawa-shi; Japanese pronunciation: [ho.so.ka.wa(ꜜ.ɕi), -soꜜ.ka.wa(.ɕi)]) is a Japanese samurai kin group or clan. The clan descends from the Seiwa Genji, a branch of the Minamoto clan, and ultimately from Emperor Seiwa, through the Ashikaga clan. It produced many prominent officials in the Ashikaga shogunate's administration. In the Edo period, the clan was one of the largest landholding daimyo families in Japan. The current clan head Morihiro Hosokawa served as Prime Minister of Japan.

Minamoto no Yoritomo (源 頼朝; Japanese pronunciation: [mʲi.na.mo.to no (|) jo.ɾʲi.to.mo], May 9, 1147 – February 9, 1199) was the founder and the first shogun of the Kamakura shogunate, ruling from 1192 until 1199, also the first shogun in the history of Japan to hold de-facto power over Japan. He was married to Hōjō Masako, who acted as regent (shikken) after his death.

Yoritomo was the son of Minamoto no Yoshitomo and belonged to Seiwa Genji's prestigious Kawachi Genji family. After successfully maneuvering himself to the position of rightful heir of the Minamoto clan, he led his clan against the Taira from his capital in Kamakura, beginning the Genpei War in 1180. After five years of civil war, the Minamoto clan finally defeated the Taira in the Battle of Dan-no-ura in 1185. Yoritomo established the supremacy of the samurai caste and the first shogunate (bakufu) which was to be centered around Kamakura, thus beginning the feudal age in Japan, which lasted until the 17th century.

Ashikaga Takauji (足利 尊氏; August 18, 1305 – June 7, 1358) also known as Minamoto no Takauji was the founder and first shōgun of the Ashikaga shogunate. His rule began in 1338, beginning the Muromachi period of Japan, and ended with his death in 1358. He was a male-line descendant of the samurai of the (Minamoto) Seiwa Genji line (meaning they were descendants of Emperor Seiwa) who had settled in the Ashikaga area of Shimotsuke Province, in present-day Tochigi Prefecture.

According to Zen master and intellectual Musō Soseki, who enjoyed his favor and collaborated with him, Takauji had three qualities: he kept his cool in battle and was not afraid of death, he was merciful and tolerant, and he was very generous with those below him.

The Tokugawa clan (徳川氏, Tokugawa-shi, Tokugawa-uji; Japanese pronunciation: [to.kɯꜜ.ɡa.wa, -ŋa.wa, -kɯ.ɡa.waꜜ.ɕi, -ŋa.waꜜ-]) is a Japanese dynasty which produced the Tokugawa shoguns who ruled Japan from 1603 to 1868 during the Edo period. It was formerly a powerful daimyō family. They nominally descended from Emperor Seiwa (850–880) and were a branch of the Minamoto clan (Seiwa Genji) through the Matsudaira clan. The early history of the clan remains a mystery. Nominally, the Matsudaira clan is said to be descended from the Nitta clan, a branch of the Minamoto clan, but this is considered to be untrue or unlikely.

The Kawachi Genji (河内源氏) were members of a family line within that of the Seiwa Genji, which in turn was one of several branches of the Minamoto clan, one of the most famous noble clans in Japanese history. Descended from Minamoto no Yorinobu (968–1048), the Kawachi Genji included Minamoto no Yoshiie (1041–1108), who fought in the Zenkunen War and Gosannen War, and common ancestor of nearly all the major Minamoto generals of the Genpei War from which the Minamoto are famous.

The Nitta clan (新田氏, Nitta-shi; Japanese pronunciation: [ɲiꜜt.ta(.ɕi)]) was one of several major families descended from the Seiwa Genji, and numbered among the chief enemies of the Hōjō clan regents, and later the Ashikaga shogunate. The common ancestor of the Nitta, Minamoto no Yoshishige (1135–1202), was the elder brother of Minamoto no Yoshiyasu, the common ancestor of the Ashikaga clan. Yoshishige was a landowner in the Nitta District of Kōzuke Province in present-day Gunma Prefecture. Yoshishige supported Minamoto no Yoritomo (1147–1199) in the Battle of Ishibashiyama of 1180 against the Taira clan.

The Nitta clan rose to importance in the early 13th century; they controlled Kozuke Province, and had little influence in Kamakura, the capital of the Kamakura shogunate, because their ancestor, Minamoto no Yoshishige had not joined his fellow clansmen in the Genpei War a century earlier.

Imagawa clan (Japanese: 今川氏, Hepburn: Imagawa-uji) was a Japanese samurai clan that claimed descent from the Seiwa Genji by way of the Kawachi Genji.