The heroine is in mourning
The Chinese idiom, H á Ogu ǎ n ā IXI á n, means orchestral music. It's from Yihai Shibei: metamorphosis.
The origin of Idioms
Qin Mu's "picking up seashells in the sea of art · Metamorphosis" says: "on the red flag, in the midst of the heroism and sorrow, there are many hot and sour stories, joys and sorrows."
Idiom usage
Used as an object or attribute; used in music, etc.
The heroine is in mourning
behead enemy generals and capture their flags - zhǎn jiàng duó qí