Totally forgot this was out now. Anyone grab it?
A lot of us are big fans of the Moryo no Hako anime, for good reasons, and I can attest to the original novel being every bit as impressive. The novel was actually the second in a series, and The Summer of the Ubume is the first. It's a rougher, more imbalanced work than Moryo no Hako, but definitely worth a read.
Vertical's website mysteriously calls Natsuhiko Kyogoku the Neil Gaiman of Japanese mystery novels, which is hilariously wrong; he's the Neil Stephenson. He does a fuckton of research, and tends to put it all into the books, which can make them a bit dry at times, but nonetheless fascinating.