3/4

With one of its protagonists a young, aspiring pianist, the leap from the title to a musical time signature is as easy as 1, 2, 3. This is, indeed, a waltz of sorts, a glide around the floor of a family's life, for the most part taking in all those bits around the edges you tend not to think about much - the kick about with friends, helping a parent prepare dinner or the way siblings bond by annoying one another.

Things are missing. The fourth beat for one, which we could take to mean the mum of the piece. She's mentioned in passing by brother and sister Niki (Nikolai Mashalov) and Mila (Mila Mihova) but otherwise just an absence in their lives, the idea of nurturing replaced by Mila's warmly eccentric piano teacher (Simona Genkova). Dad (Todor Veltchev) also drifts in and out a bit, seeming to be better at putting food on the table than connecting with the kids, at least in this moment.

Scenes also don't run fully to their end or don't quite start at the beginning, the drama often whisked somewhere else as we're about to reach what more mainstream films would consider the small moments of climax. For some, this will doubtless prove frustrating but it opens the door for us to consider the characters' emotions more than what they're doing. This is magnified by the framing - the 3:2 being around, you guessed it, a quarter less onscreen width than the regular 16:9 aspect ratio.

Director Ilian Metev wants our focus on the family physics. The idea that every action has an equal and opposite reaction is sometimes writ large. So when Mila's stress about an upcoming piano audition or recital causes her to bundle in on herself, Niki's hi-jinks become increasingly pronounced, provocative in a way that's hard to resist. "My energy goes up when yours goes down," she tells him. Equally, their dad's sometimes distant attitude causes his kids to react in ways that are intensely immediate. Given the careful construction of the film by Melev and his cinematographer - who also often focus in on a single character's reaction to something or someone out of our view, it is no small feat that the film retains a natural feel. Despite its unusual tack, it's easy to fall into its rhythm which ends, gently but unmistakably, on an upbeat.