Hard magic system

Definition

You know a magic system is "hard" when, halfway through the book, the reader can predict what the hero can and cannot do. The rules aren't exhaustively listed — they are tested on the page through costs, failures, and trade-offs.

What it's for

Hard magic licenses magic as a resolution tool: if constraints are set, its use is satisfying rather than deus ex machina. Sanderson's 3rd Law — limitations > powers — sums up the contract: what makes a magic interesting is what it forbids. It also works as an economic system: who pays the cost, who profits, who suffers?

Variants by genre

• Sanderson school: highly formalized systems (Allomancy, Surgebinding, AonDor) — magic as engineering.
• Magic-science: late Le Guin, Egan — magic obeys falsifiable laws.
• Game-like hard magic: progression-fantasy web novels with explicit tiers (Mother of Learning, Cradle).
• Economic magic: magic as a finite, marketable resource (Bennett, Founders Trilogy).
• Inherited / genetic magic: rules fixed by lineage (Jemisin, The Fifth Season).
• Language-bound magic: sympathy, true-name, runes — strict linguistic rules (Rothfuss, Kuang).
• Techno-magic: indistinguishable from advanced science (Anders, Bear, parts of Reynolds).

Common pitfalls

• A system so chatty it becomes a manual — magic kills scenes instead of feeding them.
• Rules set, then quietly broken at the climax: breach of contract.
• Trivial costs (a nosebleed): power stays effectively free.
• Over-explaining up front: every card on the table before stakes exist.
• Magic isolated from society: no institution, market, or religion organizes around it.

Examples

• Brandon Sanderson — Mistborn: Allomancy burns ingested metals, dosable by the gram.
• Patrick Rothfuss — The Name of the Wind: Sympathy follows thermodynamic laws (efficiency, loss).
• R. F. Kuang — Babel: magic runs through untranslatable gaps between languages, hence through colonial scholarship.
• N. K. Jemisin — The Fifth Season: orogeny has measurable thermal and social costs.
• Robert Jackson Bennett — Foundryside: scriving rewrites the "reality" of an object through argued rules.
• Will Wight — Cradle: progression fantasy with explicit tiered rules.
• Naomi Novik — Scholomance: magic obeys conservation, debt, and brutal academic logistics.

Writing tips

Draft a one-page "laws of magic" sheet before outlining: three founding rules, three systematic costs, three absolute interdicts. Cross a single page and you're writing a manual, not a novel. Then apply the rule of three on-page proofs: every law must be tested three times before the climax (a demonstration, a costly failure, a repurposed reuse). Miss the last two and the reader stops trusting the system. Another safeguard: keep a ratio of 1 displayed power to 2 visible limits; the climax must resolve with rules already known by the 80 % mark, never with a new ability. For the wider system's coherence, our piece on the 7 worldbuilding sins maps the typical drifts (magic without economy, religion, jurisprudence) that sink even well-designed hard magic. See also building a coherent narrative universe.

Revision checklist

• Can the reader, by mid-book, predict what the hero will try and what they can't?
• Does every power have a visible cost (body, resource, time, social tie)?
• Does the climax resolve with rules already known, with no last-minute power-up?
• Does magic have economic, political, or religious consequences in the world?