Chichibu founder and craft distiller, Ichiro Akuto, has created a vatting of single malts and matured them in Japanese Mizunara oak casks (Quercus mongolica), commonly referred to as Japanese oak.  Mizunara Oak became popular out of neccessity for distillers after the Second World War when supplies of foreign oak were difficult to source, but it turned out to be a far from ideal vessel. Mizunara's loose grains tended to cause leakage, and also created challenges in terms of timber selection and cooperage. The upside is that Mizunara oak does offer very distinctive notes. 
ABV - 46%.
Region - Saitama /Japan