He brightened a little bit at the question and with a twist, pulled one of the two tools off his new rope-based belt.

"For one thing, I made this knife with a rock I found. It's probably got a hardness level of about 4.5, it's not exceptionally strong, but it was pretty good when it came to chipping so I was able to get a sharp edge to it."

Senku didn't really consider that people who weren't used to it might find making tools from stone age gear to be a little strange.