Hiyori likes to spend her times alone fly fishing. One day, a very energetic girl named Koharu tries to jump into the cold ocean in front of Hiyori and she stops her. This ends up being the beginning of their very unique relationship.
And then you cut along its spine.
.ثمّ تقطعين على طول عمودها الفقري
Dann schneide ich entlang des Rückgrats …
Después metemos el cuchillo
a lo largo de la espina.
On glisse le couteau
le long de l’arête centrale.
Poi si infila il coltello, 
seguendo la linea della lisca centrale.
Daí, acompanho a espinha cortando com a faca.