HYPNOTIC Video Inside Extreme Forging Factory: Kihlbergs Stal AB Hammer Forging

I don't know that the video is hypnotic. That's overselling things.

It is, however, impressive to watch the forging that's being done here. I'm especially impressed with how much of the forging is done by hand, the pieces moved, rotated, shifted, pierced - all by hand.

Does anybody know the name of the tool used for the notching done at 2:55? Is it a notcher? A notching tool? A notch? A wedge? A notch wedge? Wedge notch? Triangular wedge notching tool? Notch wedge triangular prism with metal handle?