Here's my summary of what I`d be stocking up pre-Olympics:
Yamazaki Limited 2017 Yen 30,000 Amazon
Nikka 12 (Still available at Yen 5,800 around town, but already Yen 11,800 on Amazon)
Any Hibiki - available occasionally at list for NAS and Blender's choice, but this will be the dram in most demand at Olympic time, IMHO
Nikka From the Cask - Yen 2,400 but predict the will be sold or double by Olympic time
I also predict Suntory`s Royal, long available pretty widely, will be the next to see shortages, and price increase ahead of the Olympics