Now... in Japan, even though they measure in metric (using centimeters) versus the classic Imperial measurement in inches. Us Japanese have a slightly different measurement in cup sizes.
Japanese cup sizes are smaller than their western counterparts. They're only one cup difference, though. A Japanese D-cup should be a western C... but in reality it might be a B or a B+. The numbers were altered to match the population.
So in Japan the average cup size is a B+ to C if we are talking in western terms.
So.. a 70-centimeter chest with a D-cup in Japan is really a 32-inch chest with a C-cup... and it might actually be a 32-B+ if she wore a bra without trying to stuff extra flesh into it (to wear it in a manner more similar to their western counterparts) .
Japan average breast size is A cup (51% of Japanese women) in another study