I tried launching one site called Pen Japan. But what I realized is that any time I considered putting in some effort to promote Pen Japan, I was better off putting that effort into promoting Candy Japan instead. If I look for bloggers to reach out to or write guest posts, I can't justify doing it for the new site when I would much rather promote the existing one.

Why would I prefer promoting existing one? Two reasons: running two sites is almost twice the work. Why launch a new site and promote that, when I could instead push the existing site? Secondly, there are some minor scale benefits when shipping a lot of the same item. You can get a better margin when buying 1000 pieces of the same item vs. 500 pieces of two different items. So it makes sense to push hard on just one direction.

If the sites were somehow less related, but with some synergy benefits, then that would make sense. For example if I launched a buy-and-ship reshipping service where customers can request any item they want from Japan which I then go out to buy and ship to them. It would make sense to promote that, because the avenues to promote it would be different enough not to compete against Candy Japan. It would also make sense in that those services could be cross-sold, so that is something I might consider. But not really wanting to start a "Candy X" where X is just some other country.