Izumo soba is made from fresh buckwheat flour.
What they differentiate from other reqular soba is eating stlye. The way of eating of Izumo soba is called Warigo soba.
Regular soba are served with hot soup or bamboo mat which noodles are placed on in case of cold noodles.
In warigo style, noodles are served with round shaped bento box-like plates.
Those boxes are stackable and commonly provided three-tier boxes and people eat them with pouring sauce over the entire noodles.