When I first read about the giant chess game in Harry Potter and the Philosopher's Stone, and particularly Ron's decision to sacrifice himself to win the game, I was immediately reminded of a scene in the fourth book of Dorothy Dunnett's series of historical novels about Francis Crawford of Lymond. The circumstances and execution (no pun intended) are different, and the idea of human chess is by no means original to either author, but I couldn't help wondering if Rowling had ever read Dunnett.
Then when I really started to notice Rowling's persistent use of unreliable narration, another Dunnett hallmark, I wondered again. I know that the idea of an unreliable narrator is also not unique to either author (in fact one of the best examples I can think of was written by Mary Stewart), but it's not just that. It's that JKR and Dunnett used the unreliable narrator in the same way and for the same purpose -- for instance, in the first book of both HP and the Lymond series, the reader is misled via the narration into thinking an important character is the villain when he is in fact a hero.
So that's two things they have in common. Here's another: one of the subplots in the first Lymond book has Francis's mother Sybilla and her friends pursuing the creation of -- guess what? -- the Philosopher's Stone. Again, I know that the Stone has been around for centuries and Dunnett certainly didn't invent it, but it intrigues me that once again there's an element common to the first books of both series. Also, another character in the first Lymond book, Janet Beaton, is a stocky, big-hearted woman with a sharp mind, formidable courage and a staggering number of children. Sound like anyone we know? Plus (as Natasha noted in the comments to the original version of this post -- thank you, Natasha), although no mention of this is made in the book, historically speaking Janet Beaton was accused of -- guess what? -- being a witch.
There are three possibilities here, at least that I can think of:
By saying that I think JKR may well have been inspired by Dunnett I don't mean that I think she copied Dunnett in some lazy or unoriginal fashion -- the HP books and the Lymond series are far more different than they are alike, even in their handling of the elements I've noted above. But perhaps JKR found her imagination stirred by the Lymond books and her approach to writing influenced by observing Dunnett's memorable and successful techniques. By the time JKR got around to writing HP the connection to Dunnett could even have been subconscious -- after all, the Lymond books were written before JKR was born, so she could have read them in her teens, well before she came up with the idea of HP.
It's just a theory, of course. And if JKR ever says "Dunnett who?" then of course the theory will be defunct. But I'm going to keep my eyes open as I go through HP canon and the Lymond books (something I didn't plan to do simultaneously, but I'm rather pleased it's worked out that way), and see if anything else jumps out at me.
I think what I like best about the possibility of a Rowling-Dunnett connection is that it probably means good things in the end for Snape. Which is not to say he'll necessarily survive the series, but if he's anything like one of Dunnett's antiheroes (and he certainly rings that bell for me), then we're bound to learn some things about his character which will mitigate our earlier impression of him and draw out our sympathies toward him in a new way. JKR has already said that we will "get" Snape, in the sense of understanding him, in Book Seven, if not before. I'm really looking forward to seeing what she means by that.
Thanks to Erica and ajhalluk for their comments, which made me go back and edit this entry for clarity. I hope this makes it seem a little less like I'm jumping to specious conclusions.