This series can get quite intense sometimes. Ages 12+ can probably handle this.
Lots of people die throughout the series.
An elderly woman commits suicide off a boat and takes a small child with her. They both die.
In one episode there is a scene of mass suicide. Some live, some die.
The "Biwa" is a big part of this series. The Biwa is an instrument. Sometimes in scenes of battles, etc the Biwa can be heard strumming and it slowly gets louder. This can get very intense.