Mao had this approach: "Advance at the point of the bayonet. If you meet resistance, back off." That is, take whatever others won't actively defend, and keep taking until you run into something that they will.
This seems to still be China's approach, at least in this area.
China's approach has a lot to do with historical context and some really hard lessons. Like what happens if you don't take the necessary measures to make sure you're strong and strategically positioned so other people can't blockade you. In case you don't know what happens: you get colonized, other countries kidnap your heads of state until you give them land concessions, and you get pummeled into accepting opium imports. Don't think it's just U.K. and France. The U.S. is guilty too.
This seems to still be China's approach, at least in this area.