Japan has described China's military rise as a source of international concern in a major review of defence policy.
In the document, Tokyo also calls North Korea a factor for instability because of its nuclear and missiles programme.
The new guidelines will shape Japan's armed forces for the next 10 years.
Japan is changing its defence policy in response to the shifting balance of power in Asia, the BBC reports.
Forces will be bolstered in the southern islands near to China and its growing military might.
Defences will be scaled down in the north where they have been deployed since the Cold War to counter an invasion from Russia.
The guidelines also describe North Koreas' missile and nuclear programmes as a grave factor for instability.
The new strategic stance will be closely watched in Asia, where Japan's aggression in World War II has not been forgotten.
The defence review comes amid efforts to ease tensions on the Korean peninsula.
Relations between the Koreas deteriorated sharply after the North shelled a southern island in November.
A senior US diplomat is in Beijing. In their talks, the Chinese urged closer coordination over the situation on the peninsula, the BBC reports.