Good idea.(the coffeee I mean.) With all due respect, I wouldn't be in such a hurry to "heavily arm Japan." They can revert to type just as fast as the SoKo's seem to want to. And their "type" hasn't been especially attractive, when the westernized overlay gets a bit thin.
Do you really think the Japanese have forgotten that we nuked two of their major cities a scant sixty years ago?
We call the Russians and ally and they are far less trustworthy than the Japanese.
We don't need them to be like us, we only need them to be civilized. The Japanese can be counted on that much because they understand the consequences of their actions, and they have plenty to lose.