While technically not a Ryokan, the new "The Mitsui" property in Kyoto is absolutely breathtaking and has a really INCREDIBLE bathing spa. The spa is communal and unisex with bathing suits, but don't be put off it is a true sight to behold. We soaked in the various pools for hours on end. If you can still snatch a room for May, I'd take it.

We stayed there over NYE this year and the GM was an incredible host, made us feel like we were staying at a small intimate luxury Ryokan. Staff has perfect English throughout so very easy if it's your first time in Kyoto. Make use of the concierge team there, they really know how to guide you around Kyoto.