In the days of my youth all the cool kids had butterfly knives, and then we didn't.
This video shares the history of the balisong, a fantastic knife from the Philippines that was briefly hugely popular in the US. When I was young, and on my way to the 1985 Boy Scout Jamboree at Fort Ambrose P. Hill (named for a traitor,) I acquired a golden butterfly knife somewhere in Manhattan. I spun, swung, and twirled that knife for weeks until a police officer spotted me back home in Southern California and confiscated it. I never saw another one for sale.
Previously:
• Butterfly knife multitool
• Flip open a butterfly knife like a gentleman bastard
