This is definitively a masterpiece. Totally economic but very rich in symbols. Fluent transitions between scenes sometimes hinging on a single word - a spoken tree becomes the image of a tree becomes the symbol of life becomes ... etc. Fantastic acting, hovering between naturalistic and over the top - but this is possibly because the actors tend to talk straight into the camera.
Ozu is the master of subtlety. This rather simple story managed to totally draw me in. Worth another view. How to use economy to silently transport messages. Possibly not one single superfluous millisecond in the whole movie.
Next viewing I should check details on Noh plays. No idea what they are for.