I agree, once you’ve seen a successful trick it’s hard to forget it! I remember the first time I heard what a “shuck” was in Classic and it blew my mind haha. I think these days you have to get even trickier with the tricks to stay ahead of the curve.
I think the main one for me with respect to Japan, beyond the stuff mentioned already, is to park my fleet in sz61 and funnel troops to Yunnan endlessly. Here you have the option to make a Burma push and pressure India overland, or push Szech to threaten Russia, or do the dead drop on India itself via amphibious.
I’m partial to 2 transports 2 destroyers for the J1 buy to set this up, with at least 1 of these pairs placed in sz60 (to snap up the Philippines units on J2), but I almost always have these ships converge in sz61 on J2 for shucks out of Tokyo. This play is powerful enough, that its often better to just stay put and shuck from sz61, than it is to jump around with your transports or splitting your fleet, trying to take advantage of drops in sz 36 or sz 62 say. For Japan, the logistical payoff of transport launches (alternating your unloads from Tokyo over 2 rounds into 2 different sz/territories) is rarely as strong as the simple Shuck Shuck (1 move every round) since the latter keeps the fleet and transport group consolidated and puts ground units on the center without missing a beat. Shucking every round into Yunnan at your max capacity, 8 units from Japan, throughout, this is usually the best contribution Japan can make to cracking the center. Sure it might not give you Suez and Africa or the income boost from outlying territories, but trying to do that stuff before India and the center are handled is problematic anyway. So I dig sz61 until you have enough ground in Asia to force the issue.
Another build along these lines with the sz61 shuck focus, might be 1 destroyer 1 transport and then 1 factory (placed in Kwangtung.) Allows you to build transports in sz61 later on, which can be very helpful. The IJN occasionally can be vulnerable to sneaky Allied bomber movements backed up fighters, and that’s when it’s particularly useful to be able to operate out of sz61, since it’s harder for the Brits or Americans to bring fighters in range than sz36, but it’s closer to the action for Japan than sz62. So kind of a comprise on fleet defense, with the shuck as a bonus haha.
Yet another trick for Japan is to build a factory in East Indies in early rounds, as a way to lock the Allies off of it. You often don’t even need to use the factory right away, or place units there for it to be an effective play. Simply having the option to drop 4 ground, or 4 ships at a moment’s notice, can be enough to keep the Allies from getting any bright ideas about the south Pacific.
The first nation to place a factory on the money islands can often holds them for the duration, so as Japan it can be a useful trick to just buy one outright, since you start the game with the islands under your control already.