Most Western print-making techniques have used oil as the medium for printing. In Asia the weight of the tradition has been with water. This oil and water difference is also true in the field of painting.
Oil goes very well with metal machinery, it is the blood and food of metal machinery.
Water does not. Water rusts metal, but goes very well with living things that have depended on water like wood, and our own human bodies. So printing with water is best done by hand, by human presses using a baren. The emphasis on water as a medium in art and writing, and the tradition of disciplined use of the human body in the production of craft, may have a lot to do with why Japan hosts a strong tradition of 'water printing'. I have been working the craft of color woodblock print-making since January, 1993.