I don't even know where to begin with this one. The onus might be on me for expecting a thriller to be more than it ever meant to be, itself. But maybe not - the author's note at the end of the book indicates that Hayder does honestly care about getting the word about the rape of Nanking out there into the world.
I'm ahead of myself. The Devil of Nanking, as one can presume, is about the Japanese atrocities committed during its invasion of China in World War II, atrocities that Japan has never officially recognized. Indeed, to my understanding, most Japanese citizens either downplay the extent of the atrocities, or deny that they happened at all. As these events pass out of living memory, this is denial strategy will allow Japan to completely sweep the rape of Nanking under the rug of history within its borders.
Serious stuff. Which is why it's so freaking bizarre that Hayder only spends perhaps a third of her novel following the narrator telling the story of the rape of Nanking. By far the bulk of the novel is dedicated to Grey, a British woman seeking film footage from Nanking, and who finds work at a hostess club frequented by the yakuza, and who has some sexual trauma in her past and present. Grey's story involves cannibalism as a route to eternal life, and a weird backstory that comes across as an anti-abortion parable. Needless to say, it is not nearly as interesting at the rape of Nanking material, and is so frivolous as to be offensive (Grey often comes across as a more-tormented-than-usual manic pixie dream girl) in its pairing with the real-world atrocities Hayder claims to be interested in spreading the knowledge of.