I remember hearing on local radio more than 10 yrs ago now, during the 50th anniversary celebrations of the bombing of Darwin, that apparently the Japs were considering training and secretly deploying a commando group comprised of their worst criminals, to land in northern Aust and cause as much havoc as possible. Such a Jap 'Dirty Dozen' never actually happened OTL, but WI the Japs actually had done so- perhaps landing a few different groups along the NT, WA and north Qld coasts ? How badly affected would Aust civilian morale have been at the notion of armed psychopathic Japanese military conviocts loose on our shores ready to kill, maim, rape and destroy ? How much of a challenge would've been posed to the Aust armed forces to hunt down and destroy such a covert sabotage outfit ? The most similar example I can think of relates to the attempted prison break at the Cowra prison camp in NSW in 1944, when a few hundred Jap POWs rushed the guards and broke out of the camp, but all either committed suicide or were recaptured by nearby soldiers and local cops and armed civilians.