China was broken by this, used as a weapon (8)
I believe the answer is:
chainsaw
'this used as a weapon' is the definition.
The definition suggests a singular noun which matches the answer.
'china was broken' is the wordplay.
'broken' is an anagram indicator.
'china'+'was'='chinawas'
'chinawas' anagrammed gives 'CHAINSAW'.
'by' acts as a link.
Can you help me to learn more?
(Other definitions for chainsaw that I've seen before include "Powered cutter" , "Tree-lopper's tool" , "powered device" , "Timber cutter" , "Texas massacre tool" .)