Emperor Seiwa in the context of "Hosokawa clan"

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 Seiwa Genji (清和源氏; Japanese pronunciation: [sei.wa ɡeꜜɲ.dʑi, seː-]) 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, such as the Ashikaga, Hatakeyama, Hosokawa, Imagawa, Mori, Nanbu, Nitta, Ogasawara, Ōta, Satake, Satomi, Shiba, Takeda, Toki and the Tsuchiya, among others. The Shimazu and Tokugawa clans 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).

Kotohito (Japanese: 政仁; IPA: [ko̞to̞çito̞]; 29 June 1596 – 11 September 1680, posthumously honored as Emperor Go-Mizunoo (後水尾天皇, Gomizunō Tennō; [ɡo̞mʲizɨno̞ː tẽ̞nːo̞ː]), was the 108th Emperor of Japan, according to the traditional order of succession. Go-Mizunoo's reign spanned the years from 1611 through 1629, and he was the first emperor to reign entirely during the Edo period.

This 17th-century sovereign was named after the 9th-century Emperor Seiwa, sometimes posthumously referred to as Mizunoo (水尾) because this is the location of his tomb, while go translates as "later", and thus, he could be called the "Later Emperor Mizunoo". The Japanese word go has also been translated to mean the "second one", and in some older sources, this emperor may be identified as "Mizunoo, the second" or "Mizunoo II".

The Hatakeyama clan (Japanese: 畠山氏, Hepburn: Hatakeyama-shi) was a Japanese samurai clan. Originally a branch of the Taira clan and descended from Taira no Takamochi, they fell victim to political intrigue in 1205, when Hatakeyama Shigeyasu, first, and his father Shigetada later were killed in battle by Hōjō forces in Kamakura. After 1205 the Hatakeyama came to be descendants of the Ashikaga clan, who were in turn descended from Emperor Seiwa (850–880) and the Seiwa Genji branch of the Minamoto clan.

Three Genji Shrines (源氏三神社, Genji san jinja) are a group of three Japanese Shinto shrines connected with the Seiwa Genji group (the descent from Emperor Seiwa) of the Minamoto clan.

• Rokusonnō Shrine, Minami-ku, Kyoto, Kyoto Prefecture
• Tada Jinja, Kawanishi, Hyōgo Prefecture
• Tsuboi Hachimangū, Habikino, Osaka Prefecture

The Kira clan (吉良氏 - kira-shi) was a Japanese clan, descended from Emperor Seiwa (850–880), and was a cadet branch of the Ashikaga family from the Minamoto clan (Seiwa Genji). Ashikaga Mitsuuji, grandson of Ashikaga Yoshiuji (1189–1254) was the first to take the name of Kira.

The Hachisuka clan (Japanese: 蜂須賀氏, Hepburn: Hachisuka-shi) are descendants of Emperor Seiwa (850-880) of Japan and are a branch of the Ashikaga clan through the Shiba clan (Seiwa Genji) of the Minamoto clan.