Today, Dungeons & Dragons of matches saving throws to ability scores. But for most of the game’s history, D&D grouped saving throws by 5 sources: spell or staff, wand, death ray or poison, turned to stone, and dragon breath. These categories and the game’s saving throw table made me wonder: What made clerics so resistant to poison? Of all possible threats, why set aside a specific save for being turned to stone? (Also, “stone” isn’t even a source, just shorthand for a list of creatures.) Dragon breath seemed overly specific too, but at least the game’s title featured dragons. And how could the remaining 3 types of save cover every other hazard in a fantastic world?

Gary Gygax based his Chainmail rules on a 1966 pamphlet by Tony Bath titled Rules for Medieval Wargames. In those rules, attackers make a roll to hit, and then defenders roll a “saving throw” to see if their armor protects them. The heavier the armor, the easier the save.

Attack rolls in Dungeons & Dragons combine Bath’s to-hit roll and saving throw. But Gary reused the name “saving throw” for another, similar purpose. This rework begin in Chainmail, the mass-battle rules that formed the basis for D&D. In Chainmail, creatures lacked hit points, so successful attacks destroyed units. But with extraordinary individuals like heroes, wizards, and dragons, a saving throw allowed a last chance to survive. For example, the rules say, “Dragon fire will kill any opponent it touches, except another Dragon, Super Hero, or a Wizard, who is saved on a two dice roll of 7 or better.”

Chainmail’s rules for spells, magical attacks, and similar hazards led to saving throws in original D&D. The first Dungeon Master’s Guide explained the concept. “Because the player character is all-important, he or she must always—or nearly always—have a chance, no matter how small, of somehow escaping what otherwise be would be inevitable destruction.”

“Someone once criticized the concept of the saving throw as ridiculous,” Gary wrote. “Could a man chained to a rock, they asked, save himself from a blast of red dragon’s breath? Why not? I replied. Imagine that the figure, at the last moment, of course, manages to drop beneath the licking flames, or finds a crevice in which to shield his or her body, or succeeds in finding some way to be free of the fetters. Why not?” Saving throws grant a last chance, but they leave the details of why a save worked to the storytelling of the player and DM. The brilliance of hit points comes from their abstraction, and in original D&D saves are just as abstract as hit points.

Chainmail only includes saves for 4 effects: dragon breath, basilisk gaze, spider poison, and spells (just fireball and lightning). Original D&D turned those 4 saves into categories, and then added “wands” as a 5th.

The detailed numbers in the saving throw table suggest that Gary set saves to simulate nuances of the game world. However, the original saving-throw table reveals no nuances and few patterns. Fighters grow to become the best at dragon slaying. Wizards gain the best spell saves and so become best at dueling other spellcasters. But why, say, should magic users boast the best resistance to petrification? And why does the death ray from a Finger of Death spell get grouped with poison rather than staying in the tougher spell category? Apparently, when Gary Gygax told players to save or die, he also gave them a break. Go figure.

In Advanced Dungeons & Dragons, the revamped saving-throw matrix reveals more patterns.

Clerics show the best saves versus paralyzation, poison, and death magic. Perhaps divine favor helps spare them from death.

Magic users start with the best saves and end with the worst. Did Gary intend to help low-level mages and to balance high-level wizards?

Fighters start with the worst saves and end with the best. Was this designed to balance the class, or just to simulate the resilience of a front-line survivor?

Although the saving throw categories lasted 25 years, these types proved clumsy.

As D&D added countless threats, the designers folded them into the same 5 categories descended from Chainmail. For dungeon masters, these peculiar categories made guesswork of choosing the right save for a new effect.

In AD&D, characters with high wisdom or dexterity gained bonuses to saves that demanded willpower or agility. But neither bonus matched a saving-throw category. The bonuses could apply to some saves in multiple categories. Remembering these bonuses—and sometimes gaining the DM’s approval to use them—added a awkward extra step.

Third edition switched to grouping saving throws by the aptitude needed to survive the danger. Now a high wisdom or dexterity cleanly benefited will or reflex saves. Finally, a high constitution helped shake the effect of poison.

The switch made saving throws simpler, but they became less abstract. The odds of someone chained to a rock using quick reflexes to survive dragon fire seemed lower than ever—low odds that fifth edition simulates by imposing disadvantage on a restrained character’s dexterity save.

When I imagine someone making a reflex or dexterity save, I picture someone leaping and tumbling from rushing flames. Then I look at the battle map and see a figure in the same square. In my overly-complicated version of D&D, evasion would make targets move out of an area of effect.

Next: Fourth edition proved D&D works without saving throws, so why did they come back?