What is collective self-defence?

Japan's post-World War Two constitution bars it from using force to resolve conflicts except in cases of self-defence.
Mr Abe's government has pushed for a change that would revise the laws such that Japan's military would be able to mobilise overseas when these three conditions are met:
#when Japan is attacked, or when a close ally is attacked, and the result threatens Japan's survival and poses a clear danger to people
#when there is no other appropriate means available to repel the attack and ensure Japan's survival and protect its people
#use of force is restricted to a necessary minimum
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