During the 9th century the emperors began to withdraw from public life.
Delegating the affairs of government to subordinates, they went into
seclusion and, in time, came to be regarded as abstractions in the
national life rather than its directors. The retirement of the emperors
was accompanied by the rising power of the Fujiwara, the leading family
of court nobles. In 858 the Fujiwara became virtual masters of Japan,
maintaining their power for the next three centuries. In that year a
Fujiwara prince, Yoshifusa, became regent for his grandson, then less
than one year old. The Fujiwara monopolized most of the court and
administrative offices. In 884 Fujiwara Mototsune became the first
official civil dictator (kampaku). The greatest of the Fujiwara
leaders was Michinaga, whose five daughters married successive
emperors, and who was the leading figure at the court from 995
to 1027.

The period of Fujiwara supremacy was marked by a great flowering
of Japanese culture and by the growth of a civilization greatly
influenced but no longer dominated by the Chinese one, which had
been its fountainhead. The dictatorship of Michinaga is regarded
as the classical age of Japanese literature. The character of the
government also changed under the Fujiwara ascendancy. The
centralized administration, which became rife with corruption,
weakened, and the country in time was divided up into large,
hereditary estates, owned by the nobles as tax-free emoluments
for their official positions. Most peasants were only too willing
to attach their lands to such estates in order to escape the heavy
burden of taxes on the public lands that had been meted out to them.
Thus, great private estates became characteristic of landownership
throughout the empire.

In the provinces, local groups of warriors banded together for
protection, forming protofeudal groups of lords and vassals. The
leaders of these groups were often members of the Taira and the
Minamoto clans, both of which had been founded by imperial princes.
The Taira warriors acquired their military renown and power in the
southwest; the Minamoto, in the east. In the 12th century both great
military clans started to extend their power to the court itself,
dominated by the Fujiwara, and a struggle for control of Japan ensued.
In 1156 a civil war was waged between the forces of two rival emperors,
and, after a second war, in 1159 and 1160, the Taira crushed the Minamoto
and seized control of Japan from the Fujiwara. The Taira leader, Kiyomori,
was named prime minister in 1167, and, modeling his policies on those of
the Fujiwara, married his daughter to an imperial prince, their infant son
becoming emperor in 1180. In the same year the Minamoto leader, Yoritomo,
led an uprising in eastern Japan, and the Taira were driven from the capital.
The civil war endured five years, ending in 1185 with the naval battle of
Dannoura, near present Shimonoseki on the Inland Sea. Yoritomo became the
leader of Japan, ending the era of imperial administration and inaugurating
a military dictatorship that ruled Japan for the next seven centuries.