Mugitoro rice is a humble one bowl food. I believe it was originally a peasant food. In spite of the appearance, it tastes pretty good. Particularly when appetite decreases during hot summer months, the Japanese love to eat mugitoro rice.
You can combine pressed barley and rice at any ratio (by volume). You could use 100% pressed barley or 30% pressed barley, or you can do without pressed barley at all, if you are sensitive to gluten. I mixed 50% rice and 50% pressed barley this time. The more you use pressed barley, the harder the texture but barley is more nutritious than white rice.
Pressed barley looks like oatmeal. You can find it at Japanese, or Korean grocery stores, or online.
For more information, including how to choose and store nagaimo, please see here.