Well to me they’re part of an overall southeastern quadrant, with the northeastern quadrant occupied by Russia. It’s just how I think about things. If you divide it into eight directions plus a central region then it’s clearly East Asia, which is the common way to look at it.

It’s a habit of thought that I should break because it’s not really a common way to look at Asia, which makes communication difficult. It’s almost certainly a habit derived from discussion about the US, which is often discussed as four quadrants plus “the midwest,” which is really the center.