This is a really stimulating film. At a superficial glance it appears to be a bit slow and uncertain but it has so many facets to it that it holds the attention and then reveals more as it progresses.
The title is an initial hook and when the metaphor plays out it's like a strange Japanese game show taken to literally. But it is a metaphor about the difficulties of navigating married life. The central idea is demonstrated in a series of crises.
At this stage it is interesting how the men react: they are mystified and concerned. It's more likely that in a Western movie - and one that is a sort of romantic comedy like this - they'd be angry and go out and get drunk. The Japanese males are shown confused, sensitive and troubled by the turn of events, discussing what it means and why.
Further on the characters work out their ideas of married life and love from female and male perspectives; of expectations and changes in the relationship over time.
This is considered, as if from a novel, and it is true that the pace of the film could be a bit quicker, though it does resolve its ideas in other scenes as the story expands.
The idea of death as am articulation of love is explained in Japanese terms which puts the film together. This is stated as a fact, where it is a long held social myth, which has been accepted as fact. Nevertheless, it makes the film a genuinely interesting experience from a cultural angle.
One other intriguing aspect is the soundtrack which is reminiscent of an early '70s rock, with touches of a Beatles' Abbey Road sound a times; an unusual choice given the themes and story, but also made it stand out.