How it works: These saves work exactly like the standard saving throws for B/X in that they are target numbers that the player needs to meet or exceed in order to be successful. Ability modifiers affect saves in the following way:
- CON bonus/penalty applied to Fortitude saves
- DEX bonus/penalty applied to Reflex saves
- WIS bonus/penalty applied to Will saves
It should be obvious which save is applicable in a given situation. Fortitude saves are for poisons, diseases, surviving resurrection or transformation from stone to flesh, etc. Reflex saves are for dodging lightning bolts, dragon breath, wands and so on. Will is for resisting mind-affecting spells such as charm or fear.
The process for generating these was simple. I just started with a base save target of 15, and improved the values based on the charts in the d20 SRD. A normal save progression is improving at a rate of 1 every 3 levels, while good saves start out at +2 and improve at every even-numbered level.
There are a couple of things to note. First, the ability modifier range for B/X is -3/+3, so if you are going to use these for OD&D, where the modifiers only range from -1/+1, you may want to change the base save number to 14, but I will leave that up to you. Secondly, I use separate race and class, and no level limits on demi-humans, so I don't give them ridiculous save bonuses; they simply use the save tables based on their class. However, I would likely give them minor bonuses to keep with tradition. For instance +1 to all save rolls for the lucky little bastard Hobbits, and +2 vs. poison/+1 vs. magic for Dwarves. I will leave these racial bonuses, if any, to be determined by the referee, since whether or not demi-human level limits exist in your game should be a big factor in determining what those bonuses might be.
I only advanced the tables to level 10, since that should cover 99% of the games happening out there, and I've only play-tested these at level 2-3. In the event you use these for your game, and need to go beyond level 10, you should know better than anyone if the saves should continue to advance at the same rate, stop advancement completely, or advance at a slower rate. It all depends on whether or not the party has a lot of items that are giving bonuses to saves or boosting abilities beyond 18, etc.
One final note is that one of the main strengths of the original saving throw categories is the evocative names they were given. Let's face it, "SAVE VERSUS DEATH RAY" is way cooler than "Make a fort save". That being said, the save categories I present here can always be renamed in order to keep that flavor. I am not so creative when it comes to such things, but I am interested to hear what you guys might come up with.