OK, I must correct myself, this is not the one I thought it was. I was at this location before and could not get in, didn't have enough strength. So after reading this I went into game and went out there to take a look. I now know your frustration...
Here's what I did. Clean up the area around and under the Katana, even if you don't need it, just pick everything up. That way only the Katana is left. I am on PC by the way.
I swapped one of my weapons to my katana.
I jumped onto the two blue bottles next to the yellow bin facing the Katana.
Go into the 'block' position with your Katana (right button on your mouse) I have no idea what this is on console.
Move forward slightly and the Katana should show then, so you can pick it up.
Nothing really special about it, but...I understand. This can turn into a personal vendetta real quick...Good luck, hope this helps.
Let us know if you got it.