Japan, South Korea, & Guam
http://hiltonhotels.jp/sale-en
Flash Sale Terms & Conditions
Limited availability at the discounted rates. Offer is subject to availability at participating Hilton properties across Japan, South Korea, Guam and Southeast Asia (listed here), for stays booked between 5 Sep 2017, 2pm JST, and 8 Sep 2017, 2pm JST, and completed between 5 Sep 2017 and 28 Feb 2018. Offer subject to availability. Blackout dates may apply and vary by property. Rates are valid for single/double occupancy and are exclusive of all taxes, incidental charges, gratuities, and resort fees where applicable. Discount is 40% off Flexible Rate (“BAR”) and Bed and Breakfast Rate (“B&B”) across all participating properties. Hilton Honors members will receive an additional 10% off BAR and B&B.
I have an upcoming stay and I've been watching the rates for a bit. Sure enough, price for a new booking went up about 50% over the weekend. So half off of that is more like 25% off for a prepaid rate.