This is the part that kills my ability to "set it and forget it". So many things bother me about this. I know I have to do it (because Japan), but how much and on what markets?
* I don't like the idea of investing in emerging markets. Having grown up in one, I know how shady those can be and how cooked the books are. Growth is often an illusion. If an emerging market is "promising", I'd rather wait until it achieves developed status.
* Developed market indexes are dominated by Japanese stocks, which have gone nowhere in almost 3 decades. You have to accept that a good chunk of your money is going into a no-growth sink.
* I don't know what to expect from Europe. Or even Canada for that matter. When I look at those countries from a distance, I see that 1) their large corporations have been established looong ago (i.e. no new ones are created) and 2) heavy taxation and regulations in those countries doesn't seem to leave much room for profits, at least not as much as in the US. I'm probably wrong though, so please educate me.
I know home bias is supposedly wrong, but the American market is well studied, well known, highly liquid, and there's a cultural aspect to its growth in that its part of the general population's mindset to invest in it for long term goals. I don't think that's the case in all (or even most) countries.
Part of me wants to go full jlcollinsnh/Bogle/Buffet, folks who say you don't need international diversification. Another part of me wants to go as blind as possible into it and just invest in a "world index" ETF like ACWI or VT. And yet another part of me wants to do something in between but has no idea what to do :)