There are more variations in a game of chess than there are atoms in the observable universe. In her latest novel, Intermezzo, Sally Rooney has written a highly original permutation of the love story.

The book centres on two brothers: Ivan and Peter Koubek. On the surface, it seems like the brothers have little in common. Peter is a successful Dublin lawyer, who despite his chaotic social life is in firm command of the profession. Ivan is a 22-year-old chess genius; socially awkward and unsure what path he wants to take in life, he has lost the love he once had of playing competitive chess. Philosophically, Ivan and Peter couldn’t be more different. Or, at least, that’s what they think.

Both brothers are struggling to come to terms with the recent death of their father and trying to figure out how they fit in the world. Peter is self-medicating on a cocktail of drugs and in a non-committal relationship with Naomi, a college student who is more than 10 years his junior. Ivan is falling for an older woman, Margaret, who is facing her own difficult past. Ivan and Peter both have to navigate the challenges that the age gap in their relationships presents.

The novel is told from both Ivan and Peter’s perspectives in alternating chapters, demarcated by stark stylistic differences. Peter’s sections are frenetic, filled with short, sharp sentences that dart from one thought to another. As a reader, they make you feel sped-up, discombobulated. Ivan’s sections are slower paced, contemplative, as he navigates his newfound relationship with Margaret.

Throughout the novel, there is Rooney’s mastery of dialogue and the way characters push-and-pull at each other is always surprising. In chess, an Intermezzo is a move a player makes that is unexpected when there is an obvious move to be made. Rooney’s characters are often doing this, saying or doing the unexpected thing that makes their interactions wholly more believable and engrossing.