Quite some time ago after handling a gosu blue henko with thick hakeme slip by Kawai Kanjiro, I was a bit surprised at how coarse the actual slip was under the glaze. Once I returned home from Japan I started trying out various "additives" to various slips from molochite to beach sand with an array of effects. Recently I inherited a bag of rather coarse sand with small rocks in it for good measure, perhaps 50lbs or so and have been using it in my small batch white and regular stoneware clays and have moved on to making a rather thick, sandy slip out of it as well.
Illustrated is a small sandy yunomi, one of a group of pieces that I am using to test out the durability and endurance of the surface. This slip was applied with a coarse 2" brush in a vertical, albeit haphazard pattern and once bisque it was glazed in my two part Oribe that appears more amber than it does green. The surface is of this yunomi is rather coarse with a lot of actual and visual texture that is likely best suited for pots that don't come in contact with the lips but this is where I started. I suspect this is a rather good surface moving forward for vase forms and covered jars an though it bares no resemblance to the genesis of the idea, as with many of my pots, I have Kawai Kanjiro to thank for the inspiration some 30 years back.