In Japan now and there's no sign of any Natura or Supera 1600. The stores do not have any of this film anymore. A real shame to lose such great emulsions.
I guess the Japanese market must have been emptied by international film retailers doing direct imports. Some shops from HK are quite active on social media. I saw them push hard the Agfaphoto Vista films after they announced they'd be gone. Apparently they are close to running out. One shop with online sales in US$ shows Natura 1600 sold out. The other ones still have it in their price list, but that doesn't mean much because they sell offline. Their website might not be updated yet.
Even Fotoimpex imported Natura and Venus. Previously I've seen only Macodirect doing that. Fotoimpex still has stock of all Fujis. I bought a brick of Vista 400 at the normal price as a final goodby. It's nice for a consumer film, but not worth more than the €3.70 a roll, which I paid.
I have to admit that I hardly use the 1600 film. I bought a three pack in Hong Kong in 2016. Used one roll right away and the other two are still in my freezer. On my last visit I bought some more, used one roll again and now I have five rolls in the freezer. I don't want to waste it, but always wonder what would be appropriate to use it for. Large Asian cities at night are pretty good. Western cities at night are boring by comparison. But that is where I am. I guess not a big market for such film. Highspeed b/w is better suited here.
What are you doing with Natura1600 when you're not in Asia?