Disclaimer: I received an advance review copy of this book from Penguin Canada My first experience reading the work of Guy Gavriel Kay was a borrowed copy of the Fionavar Tapestry. My copy of the book has since wandered off into other hands. Later, I discovered that this author was the Guy Kay whom Christopher Tolkien acknowledged for his aid in the editing of J.R.R. Tolkien's The Silmarillion. While the Fionavar Tapestry, and his 2007 novel Ysabel meld fantasy with modern day characters, most of Kay's novels merge fantasy with historical fiction, and remain entirely in a fictional world.
As is often the case in his novels, Under Heaven takes place at a turning point in history. We are presented with a land that can go in different ways. The sense of nostalgia of the end of a golden age is here, and so is the sense that the future cannot be foreseen.
Kay presents the concept of balance in all things to be a central focus of Under Heaven, and this can be seen throughout the text. Many characters in the novel are paired, as if to balance the forces. When the balance is broken, things begin to fall apart. Tai's initial act of piety, burying the bones of both sides of past battles, is emblematic of this theme of balance.
Someone with more knowledge of Chinese history than I likely has knowledge of the period of history Kay uses as the starting point for the novel. The parallels are there, I'm sure, in the broad strokes.
I enjoyed this story more than I did Ysabel. While I did not find it quite as poignant a story as Tigana, once again Kay has written another historically based fantasy. If you've read and liked some of Guy Gavriel Kay's other novels, you will want to pick this one up.