If I purchase a 2DS from Japan, will I be able to play American games on it?
From this site:
Like the Nintendo 3DS before it, the new 2DS is region-locked, which, unfortunately, means that devices can only play games with the same region codes, and you can’t access online stores from different regions.
Since Japan is a whole different region than North America, you can't play North American games on it.
See this answer for more information on how Nintendo does region locking (its for the 3ds, but it should be identical for the 2ds).