Japan properties on points
 

Was just checking Japan properties in Osaka, Tokyo and Fukuoka and found that all of them are not available for rewards. However, when I go to the Japanese websites, I can easily access and book the room.

This has been happening since last year. Is there a blackout for the booking on Japanese properties?

As mentioned here (despite the title, the thread also mentioned Japan):
you may need to book reward stays in certain countries over the phone. The website has been having issues with rewards in countries which are redeem-only, which includes Japan as well as countries where Nordic Choice operates. It may have been fixed for some regions but not all, I'm not sure.