Sanderson’s Laws of Magic — Turn Clear Limits into Playable Choices
Brandon Sanderson's laws of magic are writing principles, not a universal specification for roleplaying games. Their value at the table is more practical: they can help a group understand what magic can solve, what makes using it difficult, and how an established ability can keep producing interesting choices.
The mistake is to turn them into a demand for exhaustive spell physics. Players need reliable information about the decisions in front of them. They rarely need a lecture explaining every supernatural event in the setting.
First: make solutions understandable
Sanderson's first principle connects magic's ability to resolve a conflict with the audience's understanding of it. At a game table, the equivalent is fair expectations. If a player spends a resource because their spell can open a sealed door, the GM should not suddenly decide that this particular door requires an unmentioned exception.
Mystery still belongs in fantasy. The players may not know why a tower floats or what a spirit wants. The distinction is whether they are being asked to make a consequential choice using an ability they supposedly understand.
Write a short ability statement: “You can move a flame you can see into an unlit nearby lamp.” Clarify sight, distance, and what counts as a flame when these become relevant. Leave the tower's ancient origins mysterious. These two approaches can coexist.
Second: put useful limits around power
Limits create decisions when players can anticipate and work around them. An ability that moves existing fire raises questions about carrying a light, protecting it from rain, and finding another source. An arbitrary chance of instant catastrophe mainly discourages experimentation.
Separate limitations from costs. A limitation says what the ability cannot do: it cannot create fire. A cost says what using it spends: concentration, time, a prepared charge, or a resource already supported by the game. A vulnerability describes something that interferes with it, such as heavy rain extinguishing the source.
Avoid stacking every category onto one ability. If it requires a rare item, consumes health, takes an hour, and fails whenever the GM wants, the apparent power may have little usable value. Start with one clear restriction and see what choices it produces.
Third: develop what already exists
Sanderson's third principle favors exploring established material before adding more. At the table, that means giving an ability new circumstances rather than constantly introducing stronger replacements.
The flame-moving character might signal across a harbor, isolate a burning section of a rope, relight a ceremonial brazier, or deprive a guard of illumination. Each use follows the same premise. The player experiences growth through understanding, even without receiving a new spell.
The setting can develop around that ability too. Lighthouse keepers may value it. Arson investigators may distrust it. A city might require covered lanterns near a sacred grove. These consequences make magic feel integrated instead of functioning as an isolated list of combat buttons.
A ready-to-use encounter
Place the party in a rain-soaked courtyard with three lamps, a raised gate, and a watchtower whose signal fire is failing. The gate mechanism is visible only when the lamps are lit. Guards will interpret the tower signal as a request for reinforcements.
Explain those ordinary facts before asking for a plan. The flame-moving ability can help illuminate the mechanism or extinguish the signal by moving its fire elsewhere. It cannot solve both tasks simultaneously without attention and positioning. Other characters can climb, distract, shelter a lamp, or work the mechanism.
That is a useful magical choice: understandable, constrained, and open to cooperation. It does not require inventing a new anti-magic material to prevent an easy answer.
When these principles are less useful
Dreamlike horror, mythic bargains, and fairy-tale magic can deliberately resist a technical explanation. Keep that atmosphere while making the game's procedures and player consent clear. Unexplained magic does not excuse inconsistent adjudication.
B3's recommendation is to use the laws as questions during preparation. Can the players understand this solution? Does the limit create a choice? Have I explored the ability already present? Those questions improve adventures more reliably than a longer spell encyclopedia.