My knife.
Actually, not even that. I enjoy anthropology, and can climb the technological ladder to relative comfort within about two days. One day in my native forest.
More seriously: a good knife, fishing line/hooks, and a tin cup. Blanket if I didn't dress for the occasion.
Everything else can be made quickly, but those manufactured tools are SO MUCH easier than carving bone with the wrong kind of rock.
What kind of answer are you looking for, though? Ultralight primitive or loadout thread--but with explanation attached?
