If Japan does not isolate, that structure never arises. Japan is a large country (equal to France and Britain combined, roughly). And (IMO) if Japan was engaged in large-scale foreign commerce early in the Age of Sail, then Japan would participate in the expansion of oceanic commerce over the next two hundred years, with a presence around the world comparable at least to France or Britain. It wouldn't require a massive effort by Japan, anymore than the European manifestations did - it's just what happens with a successful seafaring nation.
One huge question is: does Japan get accepted as a peer among the maritime nations? I.e. are they treated as "white men"? Is Japan recognized as a "Westphalian" nation? Can Japanese ships call at European ports on the same terms as ships from other European countries?
This has huge consequences for the way Europeans view the world. And indirectly for other peoples, too - instead of "natives" versus "white men", it will be "natives" versus "white men" and Japanese. And Japan will never become Europeanized as in OTL.
Or do the European-Japanese relations turn hostile, with Japan seeking sole control of the western Pacific and perhaps more, and Europeans excluding Japan from other oceans?
Japan would probably end up colonizing Oceania.