Ontake distillery is using only sherry cask for thier whisky, so all thier single malt bottles are sherry cask whisky (Not sherry finish)

 There is a natural water spring in Ontake dsitillery which is located on the hill where we can look down the Sakurajima, which is the symbol volcano of Kagoshima prefecture. That hot spring is providing more than 1,000 L per min and that water is very soft. 

 Ontake distillery was founded by Nishi Shuzo which is the well-known leading Shochu distillery with the name of Tomi No Hozan which is one of the most major brand.
 They have thier own lab with various yeast archive and they pick up some thier own yeast for thier whisky.