Yamahai or yamahai shikomi 山廃 is a special type of sake that is independent of grade. Yamahai is related to the yeast starter stage of sake brewing, where more sbacteria and wild yeast is allowed to have an effect on the flavor. In short, the flavor is earthier and gamy, with higher acidity and sweetness due to lactic acid which develops naturally. Yamahai is generally wildest and gamy-est on the whole, kimoto is generally less so. Everything else (99% of what is out there, i.e. anything not kimoto or yamahai, collectively known as sokujou or fast-brewing moto) is comparatively much cleaner and lighter. Still, there are a wide range of yamahai/kimoto flavor profiles, some strong, some mild.
