Unflavored sake is acceptable without Hashgacha. Flavored sake (e.g., Coconut Sake) and sake which states on the label that it was aged in wine casks require Hashgacha. Nevertheless, due to potential Kashrus concerns, it is preferable to only consume premium sake labeled as Honjozo, Ginjo or Daiginjo.

From The COR: Bake Station Rye Bread
Bake Station Bakery Rye Bread sold after January 27 2005 is not Yoshon until further notice.