Black actor Noma Dumezweni has been cast as Hogwarts’ brainiest pupil in Harry Potter and the Cursed Child. The decision is a welcome challenge to the assumption that heroes are white by default

Is Hermione Granger black? This is the question prompted by the casting of a black actor, Noma Dumezweni, as Hogwarts’ cleverest pupil in an upcoming theatre production of Harry Potter and the Cursed Child. The answer is twofold. First, why the hell not? Second, what a stupid question!

A better one to ask is whether Hermione – or indeed any fictional character – is necessarily white. The answer is no. The decision to cast Dumezweni, an Olivier-award winning actor currently performing at the Royal Court in a lead intended for Kim Cattrall, challenges our assumption that characters are white unless we’re told otherwise.

Facebook Twitter Pinterest Paul Thornley, Noma Dumezweni and Jamie Parker who will play Ron, Hermione and Harry in Harry Potter and the Cursed Child. Photograph: Handout/PA

For a start, Rowling never explicitly describes Hermione’s race or skin colour. She is the daughter of London dentists, born in the Muggle world, brought up in the magic world, destined to be an outsider in both. A typical mixed-race or second-generation experience, in other words. In the first book, the smartest, gutsiest girl in children’s fiction since Anne Shirley (Anne of Green Gables) is introduced as having frizzy hair and big teeth. In the Prisoner of Azkaban, she is described as “very brown”. And Rowling, in response to some fans who find the idea of a non-white Hermione less plausible than a universe of posh magic boarding schools with no fees, confirmed the ambiguity, however deliberate, when she tweeted this week:

J.K. Rowling (@jk_rowling) Canon: brown eyes, frizzy hair and very clever. White skin was never specified. Rowling loves black Hermione 😘 https://t.co/5fKX4InjTH

Not that it matters what Rowling envisaged. We don’t need Shakespeare to have imagined Hamlet as a black man (or, indeed, a woman) to do so ourselves.

Nevertheless, few of us will have imagined Hermione as black. I certainly didn’t, reading the books as your average Anglo-Indian girl starved of black and Asian characters in mainstream culture. Especially leading characters with proper storylines, personalities and love interests. I imagined Hermione as, well, Emma Watson. The default assumption of whiteness is so strong and unspoken, it’s a hard habit to kick. The same is true of our heteronormative culture, which is why JK Rowling had to spell it out to us that Dumbledore is gay.

Facebook Twitter Pinterest Emma Watson as Hermione in Harry Potter and the Chamber of Secrets. Photograph: Allstar/Warner Bros

It turns out that Hermione is an ideal candidate for racebending (changing the race or ethnicity of a character routinely portrayed as white) and has long been reconstructed as black, biracial or Asian online, particularly in fan art, which Rowling has also been tweeting in support. Why? Because in a series that is as much about the evils of racial supremacy as anything else, Hermione is in a Muggle-born minority and is often the target of racial abuse (Draco Malfoy calls her “filthy little mudblood”). She is also an activist who understands and will stand up for the oppressed, whether people, giants or Hippogriffs, and who campaigns for an end to the enslavement of elves. Hermione is female, clever, strong, good, attractive, loyal, not necessarily white, and now, for the first time, black – and all at the same time.