I have found in general it is better to book well in advance especially if the exchange rate is better than usual at the time. We did this in November for a trip starting 3 weeks today although most are at pre-paid rates. Most of our hotels are now more expensive although in Kyoto I have seen some decent rates for a couple of days we have a hotel that can be cancelled at no cost.

However it is low season and in a post Covid world and with mask rules likely to disappear in May suspect pricing could get a bit hairy as the year progresses. Lots of locked up demand etc.