Saw this today, it's wonderful:
http://www.theguardian.com/film/2016/apr/14/our-little-sister-review-an-exquisite-portrait-of-family-life
Even better, it's set in Kamakura - in Easter last year Emily and I hiked through those exact hills and along the same beach - and she's the same age as "our little sister"! The film gets a bit soapish at times, but it's also a very good documentary of modern life and mores in Japan. It's on at the Renoir - lovely cinema just been refurbished, very comfortable and amazing screen and sound.
The arrival of a half-sister they’ve never met before subtly undermines the existence of three twentysomething women in Hirokazu Kore-eda’s tender tale