I bought a black light flashlight yesterday and started looking at my banknotes. So many of them have inks on them that are active. All the current Chinese Mao notes lite up. The designs are on the bills but when under a black light they are enhanced. The 50 yuan has a sun peeking out above the clouds over the Potala. On all of them on the obverse, above the visible denomination, is an image of the denomination that shows up under a black light. I cannot figure out how to get a picture of them but I recommend the new view of my banknotes.