Source Wikimedia-Public Domain
Ukiyo-e means "Floating World" and I have been fascinated with this form of artistic expression since about 1969 when I saw a reproduction of a Japanese Print that my art teacher in high school showed me.
During this period a number of Japanese artists started print making using blocks of cherry wood which are turned into engraving plates by removing excess wood with small knives, and utilizing one single woodblock for each color to be printed.
Step 1 is to create a detailed line drawing, carve that out into a block of cherry wood, and then print that line drawing as many as 100-150 times. W.J. Phillips in his book mentioned that he was able to get a maximum of 150 prints before the block would degrade from the process.
The watercolor paper is kept wet with water during the printing process. The wet paper is laid on top of the block, after the colored pigment (watercolor) is painted on the block. The back of the paper is then rubbed with a block of wood wrapped in leaves. Each impression is then stacked in a pile wet, with newspaper in between each layer.
There can be as many as 10 colors in each print, meaning that there have to be 10 blocks, so the printing process is a long and arduous one.
However the Japanese discovered a beautiful way to expand their markets by providing limited editions of watercolor paintings. In essence they are not necessarily exactly the same because each wash that is applied can have it's own subtle difference from print to print.
Here are some Ukiyo-e resources that you may find interesting.
A guide to Ukiyo-e websites
Empty Easel-A Brief History of Japanese Artprints
The Woodblock Prints Of Ando Hiroshige