I watched it this week too and then discovered that same video essay which I think is the only way to fully appreciate it! I've never known a film as subtle as this where the full story is hidden away in blink and you'll miss it shots. Still not entirely sure if that's a good thing or not, but it's incredibly brave filmmaking.
From what I can gather, there's a TV series that contains the prequel and sequel to this (along with some unconnected episodes). I think some of them are available but haven't been subtitled.
I think the only reason this one is fully subtitled is to fit in with the awkward western NHK World presentation (which they absolutely nail).