Complex sentence: Prior to the eighth century, perhaps the most widely made rice wine was so-called overnight sake, or hitoyozake (一夜酒), made by allowing cooked rice or rice gruel to ferment naturally.
Split into simpler sentences: Prior to the eighth century, perhaps the most widely made rice wine was "hitoyozake" (一夜酒) or so-called overnight sake. This was made by allowing cooked rice or rice gruel to ferment naturally.