In general most of the die rotation of Japanese coins were this:

which means that it is usually orientated to the dot at the top.
Occasionally there are some that are orientated to the bottom two dots at the bottom, which is about 5 degrees rotation:

Note that these coins were all minted in coin orientation, i.e. up and down when you flip the coin sideways.
Now this is the largest error of all:

Only seen in numismatic literature, Japanese error coins are exceedingly RARE if you don't believe in me!
And to think that I was about to sell the whole lot as scrap copper coins does shudder me for a bit.