The Original Text for this Rule System was located at Intwischa.org and is no longer available there, but the gist is as follows. Whenever you use anything with a limited number of uses, be it charges, ammunition, spell points, etc., you roll the die based on that item. For instance, a d12 quiver of arrows, you roll a d12 when you shoot. If you use something such as rapid fire or multishot or a spell that uses multiple spell points, you roll more than one die. If any of them come up a natural 1, you go down a die type. On top of that, after each battle that you use an item, whether you roll a 1 or not, you still go down one die type. In the case of the arrow example, had you rolled a one at some point, you would go down to d10, then at the end of that battle, down to d8.
This continues to d6, d4 and finally 1 item remaining. To know how much you have, reference the following:
1=1
2-4=d4
5-8=d6
9-13=d8
14-19=d10
20-29=d12
30+=d20 and subtract 30 from the total and determine another die type based on the chart above, so a Wand with 50 charges has d20+d12 charges.
