As much as I loathe leaders of most countries inc. those of Japan , at this point in time what Japan NEEDS they get from the USA so should not be on Trump’s “ hit list “ . They are never again going to buy our cars ; theirs are some of the best in the world . We don’t make TVs any longer . All of the US computers are made in China . Etc...etc...What is it you’d like to see them buy from the US ? Besides our debt that is .
When it’s cheaper to build in the USA, companies will build here. If you don’t have the unions, regulations, epa etc etc, companies will build here.
But to answer your question, Military assistance, entertainment, a "good faith" Marshall Plan repayment, medical devices, airplanes, high end consumer electronics among others. I admit I am reaching here.