This is the unglazed surface. Very heavily grogged, very large grog particles.
Clay is vitreous and heavily grogged. But it is white burning. Notice the orange color is developing at the glaze/body interface and shows where the glaze is thin. This is glossier than what one would normally expect a Shino to be.
Traditional Japanese high feldspar glazes having cream to orange color flashing or blushing. Potters today seek to emulate the Shino appearance using a wide range of recipes.