Would modern radar on every Japanese warship have allowed Japan to win the Second World War?
Short answerNo; it would improve detection and some battles, but not the supporting systems or industrial balance needed to win the war.
NotesModern radar would give Japan a large information advantage, particularly for night fighting, while also producing emissions an opponent could detect. Better detection would leave other limitations in place: existing anti-aircraft guns, the absence of accompanying missiles and uncertainty over suitable two-way radios for fighter direction. Japan could win additional battles without acquiring the means to overcome the combined industrial production of the United States and British Empire. One projected Allied response is to complete the European war first and wait for an even larger carrier force. The distinction is between improved information and the complete set of capabilities needed to exploit it.