-exported from Wu to the north.

Wu never attempted to conquer the whole of China, but endeavoured to
consolidate its own difficult territory with a view to building up a
state on a firm foundation. In general, Wu played mainly a passive part
in the incessant struggles between the three kingdoms, though it was
active in diplomacy. The Wu kingdom entered into relations with a man
who in 232 had gained control of the present South Manchuria and shortly
afterwards assumed the title of king. This new ruler of "Yen", as he
called his kingdom, had determined to attack the Wei dynasty, and hoped,
by putting pressure on it in association with Wu, to overrun Wei from
north and south. Wei answered this plan very effectively by recourse to
diplomacy and it began by making Wu believe that Wu had reason to fear
an attack from its western neighbour Shu Han. A mission was also
dispatched from Wei to negotiate with Japan. Japan was then emerging
from its stone age and introducing metals; there were countless small
principalities and states, of which the state of Yamato, then ruled by a
queen, was the most powerful. Yamato had certain interests in Korea,
where it already ruled a small coastal strip in the east. Wei offered
Yamato the prospect of gaining the whole of Korea if it would turn
against the state of Yen in South Manchuria. Wu, too, had turned to
Japan, but the negotiations came to nothing, since Wu, as an ally of
Yen, had nothing to offer. The queen of Yamato accordingly sent a
mission to Wei; she had already decided in favour of that state. Thus
Wei was able to embark on war against Yen, which it annihilated in 237.
This wrecked Wu's diplomatic projects, and no more was heard of any
ambitious plans of the kingdom of Wu.

The two southern states had a common characteristic: both were
condottiere states, not built up from their own population but conquered
by generals from the north and ruled for a time by those generals and
their northern troops. Natives gradually entered these northern armies
and reduced their percentage of northerners, but a gulf remained between
the native population, including its gentry, and the alien military
rulers. This reduced the striking power of the southern states.

On the other hand, this period had its positive element. For the first
time there was an emperor in south China, with all the organization that
implied. A capital full of officials, eunuchs, and all the satellites of
an imperial cour