Why is the PlayStation confirmation button O in Japan?

If you have ever played a PlayStation game in Japanese you may have noticed that the O and X buttons are used the other way around. But what is the reason behind it?

Back in the day when I installed tools like the file manager ULaunchELF on my PS2 and while testing the Japanese versions of 'Dragon Ball' games (which has another music score and that made me interested in changing it myself...) I was for the first time confronted with the difference in the function of the controller buttons. 

For some time I didn't question the reason behind it, but there's more to it which is quite interesting.

It's generally a cultural thing: As in western countries we are used to have an X to confirm something like marking the right answer in a quiz for example.

'X' means 'wrong' - not just at the Japanese PlayStation

In Japan they have a different association: The X is used for an incorrect answer in a test. It's meaning is ばつ (batsu) and has a general meaning for something negative like giving up and 'wrong'. So for in Japan it would be wrong to use it as a confirmation button.

The circle on the other hand the circle with the meaning まる (maru) has the meaning of 'correct' since the correct answer in a test is marked in a circle.

These can even be shown in gestures with arms or hands. Or in right-or-wrong games like 'batsumaru'.

This difference in terms of school tests corrections is actually a topic in the Detective Conan episodes 779 & 880 where a Japanese teacher who lived in America got it wrong after returning to Japan...

Looking at it from this perspective the different usage of the buttons makes totally sense.