The cloistered emperor Toba dies in 1156, and his deposed eldest son Sutoku elects to leave the monastery and regain his place on the imperial throne, currently occupied by his twenty-eight-year-old brother Shirakawa II.

Two factions of the imperial family, one favoring Sutoku, the other favoring Shirakawa, turn to the powerful Minamoto and Taira families, rival samurai orbushi clans, for help.

To settle the court dispute, the samurai clans apply military force in an action known as the Hogen War, aiding the victory of Shirakawa and his adherents, who drive Sutoku into exile and kill most of his supporters.

Minamoto no Yoshitomo, along with Taira no Kiyomori, supports the Emperor Go-Shirakawa and Fujiwara no Tadamichi, while his father Minamoto no Tameyoshi, then head of the Minamoto clan, with his young son Minamoto no Tametomo and Taira no Tadamasa, sides with the retired Emperor Sutoku and Fujiwara no Yorinaga.

Minamotono Tameyoshi, although he is most famous for his involvement in the Hōgen Rebellion, is also said to have intervened in a number of other conflicts earlier in his life.

Around 1113, the ongoing rivalry between the warrior monks of Mii-dera and Enryaku-ji erupted into outright violence in the streets of Kyoto.

Though the palace guard mobilized quickly to protect the Emperor, it is said that Tameyoshi, with a handful of mounted samurai, drove the mobs away himself.

Upon being defeated in the Hōgen Rebellion, Tameyoshi takes the tonsure and is released into the custody of his son Minamoto no Yoshitomo, who then has him beheaded.

This is an unprecedented breaking of Buddhist values in Japan, yet no one in the court berates Yoshitomo for his actions at the time until after his death.

Minamoto no Yoshitomo becoes head of his clan after the death of his father and together with Taira no Kiyomori, succeeds in establishing the two samurai clans as major new political powers in Kyoto.

Emperor Shirakawa II had abdicated on September 5, 1158, in favor of his son, but his abdication had implied no cession of political or other powers to his successor.

He has attempted to continue the long-customary practice of ruling in actuality from a cloistered position, but real power has begun to be wielded by the heads of the Taira and Minamoto clans, the leading samurai families.

The simmering feud between the two clans, long suspicious of one another, has escalated as jealousy and friction increases and the Minamotos plot to rid themselves of their rivals at the imperial court.

In late 1159, Taira no Kiyomori, head of the Taira clan and supporter of Emperor Nijō, had left Kyōto with his family on a personal pilgrimage.

This has left his enemies, Fujiwara no Nobuyori and the Minamoto clan, a perfect opportunity to effect an uprising.

Fujiwara no Nobuyori and Minamoto no Yoshitomo see an opportunity to effect changes they seek in the government in early January 1160.

With a force of roughly five hundred men, they attack in the night, kidnapping former emperor Emperor Go-Shirakawa, and setting fire to the Palace.

They also abduct and imprison the current emperor, Emperor Nijō, who supports their enemies, the Taira clan and Fujiwara no Michinori.

They next attack the manor house of Michinori, setting it too aflame and killing all those inside, with the exception of Michinori himself, who is captured later and decapitated.

Nobuyori forces Emperor Nijō to name him imperial chancellor, completing one of the first important steps towards gaining power over his rivals.

However, Taira no Kiyomori returns soon afterwards, with his son Taira no Shigemori and a small force.

The Minamoto, reinforced with men from Kamakura led by Yoshitomo's eldest son Minamoto no Yoshihira, are the larger force but are unprepared, and hesitate at Kiyomori's return.

The Taira are thus allowed to return to their family's mansion in the Rokuhara district, where they plan tactics and strategies, and gain many more warriors.

At the end of January, the Taira smuggle the Emperor Nijō and his empress consort out of the Sanjō Palace and into the Rokuhara mansion, disguised as a lady in waiting.

Meanwhile, the Taira also help the former emperor Emperor Go-Shirakawa escape from the Minamoto as well.

Minamoto no Yoshitomo and his men prepare to defend the Palace on the morning of February 5, against the inevitable Taira assault.

The defense holds out for a time, until a portion of the Taira feign a retreat, luring Minamoto warriors out of the Palace, and giving the rest of their force an opportunity to rush the gates and, soon afterward, drive the Minamoto out.

Yoshitomo's men are then obliged to attack the Rokuhara mansion.

Failing in their assault, they flee Kyoto, meeting resistance along the way from the warrior monks of Mount Hiei who they had attacked in decades past.

Although Yoshihira had fled the battle, and lives peacefully, in disguise, for a time in Kyoto, he is soon captured and killed by Taira no Kiyomori, the head of the enemy faction.

The Tairas emerge victorious to become the effective rulers of Japan.

At the direction of Taira-no-Kiyomori, the Tairas kill rival clan leader Minamoto-no-Yoshitomo, together with all his kinsmen at court, sparing only four young sons.

One of these, the thirteen-year-old Yoritomo, is taken hostage and raised in Kwanto, in eastern Japan, by Hojo Tokimasa, a Taira relative.

Taira no Kiyomori seizes Minamoto wealth and land, and will eventually form the first of four samurai-dominated governments during the feudal history of Japan.