I understand that the word basement means:

part of a building that is wholly or partly below ground level

But

I wonder what American English and British English call ‘the first basement floor right below the first floor of a building’ and “the second basement floor beneath the first floor of a building’.

Is this right to call it ‘basement one’ and ‘basement two” in both MaE and BrE?

What the Chinese call this type of floor as indoor floor (O/C, or underneath floor): underground floor. The underground floor is as evidenced by this link: http://www.eichacha.net/underground%20floor.html. When

do we use the English Terminology in colloquial ame and brae, or is it more technical?

What is going on in business community of Tokyo, Japan, where there is some training going on and putting some new materials together so that an ordinary person can learn something besides its basics?