Methods/Systems: Japan's Bills

Paul, my friend living in Japan, kindly shared a second gem (for the first one, click here) with me:

In Japan, each denomination of paper currency has its own raised watermark in one of its corners, which is used blind people to deduce its value. The Yen, however, is not the only currency that is easily read by the blind, here is an article about currencies around the world and how they accommodate the blind in their design.

In the U.S., the bills are all the same size and aside from their printing our notes do not have any distinguishing marks based on their value. It seems that most blind people in the U.S. employ a system of folding for their money (i.e. a $5 would be folded in half, a $10 in thirds, a $20 in quarters etc...) and several members of the blind community oppose a possible redesign.