ESHIKOTO is a Japanese sake brand established by Nizaemon Ishidaya who is also the owner of Kokuryu Sake Brewery.
"Eshikoto," is a new addition to the ESHIKOTO brand and was inspired by Kimoto brewing which means using natural lactic bacteria to produce lactic acid for sake brewing. 
 
This special sake is only available at Ishidaya Eshikoto located in Fukui Prefecture and is not available outside of Fukui or Japan. Super hard to come by.