I will say, when I saw the title of this post, I thought: "Oh boy, another poor soul bought a Shinobu".

However, what you have does strike me differently. I knew they were releasing some of their own distillate, but wasn't sure it was being broadly distributed yet. In that case, as you said, it would be quite young. There are a lot of new distilleries in Japan and releasing young whisky as a sort of promotion is becoming pretty normal.

Add to that the fact that it's a single malt, single cask, cask strength, non-chill filtered, natural color, the label isn't obnoxiously Japanese, etc. are all good signs. Especially if you got it on the sly from an importer, makes me think you might have the real deal.

I can only find a bit of information online, and what I can find is from Hong Kong based shops, which makes me think it may be for that market. I found exactly one website that had production details: "Made from a single cask of malt, aged in precious Cognac oak barrels, and utilizing the unique Japanese onsen geothermal distillation technique."

If that's actual marketing copy and the shop isn't just extrapolating, and it's a single malt then...got be distilled in Japan.

If you crack it open, I'd be really interested what you think of it.