User blog comment:JsA1/What are H!P Blu-ray Disc Regions?/@comment-131168-20150513131736

If Amazon's listings are reliable, it varies per disc. It says the one you were interested in and its immediate predecessor are Region A (リージョンコード: リージョンA), but says the 2015 Winter Blu-ray is region-free (リージョンコード: リージョンフリー).

It would be helpful to find some product shots of the sides/back where that sort of information is properly found, but stores don't put much priority on that...