Japan invaded Korea with 200 thousand soldiers in the late 1500s. Did any European country field so many soldiers in a campaign? Were the Japanese tactics and technology at a similar level of development as, for example, a Spanish Tercio?
While authors differ on the size of the invasion force I need to point out here that according to the Mōri clan records (surviving letters), the size of the invasion forces were:
While I can't speak for the size of European armies, I do need to point out that any comparison is hard due to different population, Japan having much less emphasis on its navy, and that Japan concentrated on one campaign, while Europe often needed to pay attention to many.
Now to get the easiest out of the way, there is no way any East-Asian power at the time could match one of Europe's war fleets, whether in size or technology.
Moving on to land, technologically the Japanese were fairly close to their European counterparts in terms of infantry. Japanese had firearms, pikes, and mass-produced armor. Japanese firearms and armor tended to be slightly lighter and weaker than that of Western Europe, but in the field might not have mattered that much. However, if you examine the Japanese compositions found here, with the European armies I described here and /u/hborrgg describe here, you can see that the Japanese foot had far more troops that were neither pike nor gunners, and in a fight would have been badly outnumbered in both. Pikes aside, given that many Japanese primary sources during the Korean campaign state the importance of firearms, being outgunned would probably not be a good thing. The Japanese field army was also almost completely lacking in artillery which, again, couldn't have been a good thing for them.
By the turn of the 17th century, we can probably expect combat formation to look something like this or this, with subunits in thin lines one or two ranks deep, guns in front and on the wings, pikes and spears in the middle and rear, and the commander and horsemen in reserve. The few archers remaining on the battlefield covered the gunners when they loaded. After the exchange of missiles, the pikes and spears would move in front, and the pikes would either fence and bash at each other, or the spearmen would charge and try to break the enemy. Both are attested in (different) military treaties. The pikes, it's probably safe to assume, could also be used to screen and brace against charges, especially of the horsemen who try to break through.
What this tells me is that, tactically, in the 17th century the Japanese were still experimenting with what's the best way to fight, and in some ways, the formation is similar to the Swedish brigades at around the same time early in the thirty years war. It might be thought like convergent evolution, where both started out differently but slowly moved towards the same tactical deployment, namely a group close-combat warriors with two groups of shooters on the front and/or flanks. There were, of course, many key differences such as much shallower subunits, much more variety of equipment, small group horsemen in the rear instead of each unit instead of largely concentrated together on the flanks, and of course lack of artillery.
