If we must start with a PoD no earlier than the actual start of the Pacific War, "victory" for Japan needs to be defined very minimilistically. As others have so well pointed out, there are no realistic series of military victories Japan can acheive that would counterbalance the massively disproportionate economic and military balance between the US and Japan. Japan is eventually going to lose, militarily. "Victory" can only be considered as a result that somehow lessened the impact of total military defeat - to sort of make Japan an "Asian Italy" in the eyes of the USA, UK, and (eventually the USSR). To do this several things have to happen, none of them likely:
Politically and diplomatically, Japan must:
(1) pursue a policy toward its conquered territories that is neither harsh or exploitative,
(2) strictly adhere to the Geneva accords regarding treatment of alliwed POWs
(3) win a few more battles such as as Midway
(4) Once it becomes obvious the US and UK are pursuing a "Germany first" strategy, find ways to implicitly or explicitly break with Nazi Germany, such as by offering asylum to Jews and others (something Japanese occupation authorities in Shanghai silently did).
(5) When still in a position of apparent strength, begin offering to negotiate a "land for peace" armistice with the aim of ending the war with the original Japanese Empire still intact and with some of the conquered territories perhaps up for discussion - including an offer to become a co-belligerent in the war against Germany.
(6) Remove the core clique of militarists who started the war from power
Although this is a stretch, it might be possible for Japan to end WW2 in a situation somewhat akin to Italy or Finland. Stripped of all of its wartime conquests on mainland asia, but unoccupied, independent, not completely disarmed, and still with some original possessions in hand. Depending upon what happens in China and with the Wallie/Commie split, Japan may be soon ready for an alliance with the USA as a more equal partner. This is about the closest Japan could hope to come to "victory" and it would take an amazing change of heart, both among the Japanese ruling elite and the UK and USA.