In Japan, the Yayoi culture, based on rice farming and possessing bronze and iron technology, expanded northward and eastward from Kyushu Island into Honshu. This led to a rise in population, and to increased warfare, leading to the rise of many powerful and warlike chiefdoms – Chinese chronicles of the period refer to the “100 kingdoms”. This situation is revealed in the remains of well constructed wooden hilltop fortresses dating from this era. At least some of these chiefdoms paid some for of tribute to the imperial Han court in China.
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