If things go sideways between France and Germany at some point I think perhaps Japan could wind up with Madagascar if France is really hard up for cash. Or you might get some weird horse trading at the end of a pan-European War where Japan gets it in lieu of something else.
Not overly likely but it isn't impossible. But I think it would be more of a European POD than a Japanese one.
I agree what Japan during the Scramble for Africa was hopelessly outmatched, so it is difficult to make a Japanese POD. But how about African POD?
In WWI, the German East Africa have put a terrible fight to Britain and Belgium. But imagine the Battle of Lake Tanganyika went wrong for British, cascading into more defeats due disease and ambushes. As result, British recruitment/drafting campaign among natives is less effective, and Lettow-Vorbeck receive more recruits. In 1916, all troops from South Africa and Belgian Congo may be still stuck in Africa, instead of joining the European war. German East Africa may turn in such a thorn in British side, what they will ask for assistance from somebody qualified in jungle warfare..and Japan may send a small detachment (no larger than division), which with some luck may defeat Lettow-Vorbeck force. As British goal was a secure rear and not a colony itself, there is a non-zero chance of Japanese receiving a limited mandate in German East Africa after WWI. May be of Lebanon size?
