So how would Russia respond if Japan invades Sakhalin? Would they just give them a ultimatum? Well considering that the UK didn't do the same to Argentina means that it would be conventional until a certain point right? Is that the current precedent? Closest we ever got to that is if Ukraine would have stolen KNPP but they got stopped kinda halfway short at best.. How long do you think it would take Russia to respond? I think their most modern fleet was the Pacific fleet but also a lot of submarines. Seems pretty risky to even try to take it. They pretty much gotta bet they could take control of the Island fast and somehow Russia is off guard.