The Sap Wallet
Joshua Morale of Stick and Knife Fighters of the World (stickfighting.ning.com) referred me to the “sap wallet,” something I was not familiar with. It sounds like a very handy weapon. I have spoken of the merits of saps here, which is a little-known category of weapon.
The sap wallet, designed by Fred Perrin, can be seen in action here. In essence, you put coins into the bottom of the wallet, which is swung like a sap. The sap wallet resembles a prison weapon in which a bar of soap is placed into a sock and swung.
The Atienza Kali people have a video here in which they showcase a weapon called a “trapo,” which is a weight in a sock. The sap wallet could be wielded with these techniques. (As an aside, “trapo” is Spanish for “rag.” In the Philippines vendors at intersections sell rags sewn into circles like potholders. Drivers buy them for a few pesos to wipe their cars or to help them hold the steering wheel in the blistering heat.
I would categorize this as a semi-impromptu weapon, in that it is a weapon that would fit into your environment and that you have selected ahead of time for its suitability as a weapon.