I bought an onigiri at Family Mart yesterday and it had a label touting the use of "musen rice" (無洗米加工). Musen rice is produced by a relatively new process and allows for rice to be cooked directly without first washing the rice several times with water. It has become pretty popular because of convenience. It is also argued that it takes a little less overall energy. The taste is not changed though, so it is pretty confusing as to why this would be a selling point. If anything, it has a slightly less "natural" image.