Exactly 40 cards
No more. No less. The deck is the deck.
A community-built 40-card constructed format
DUAIITY
Build With Less, Play With More.
Fast games, brutal choices, and a signature mechanic that turns every duplicate into a decision.
40Cards
15×2Nonlands
10Lands
20Life
Why Duality
Less filler.
More actual game.
Duality compresses constructed Magic into forty cards without shrinking the strategy. Every deck contains fifteen paired nonland cards, exactly ten lands, and no dead weight that wandered in because humans fear empty deck slots.
The result is a faster format where deck construction matters before the first draw and every duplicate can become fuel for Resonance.
Core rules
Simple enough to learn.
Deep enough to break.
15 unique nonlands
Exactly two copies of each, for 30 nonland cards total.
Exactly 10 lands
Basic lands in any mix. Any nonbasic is limited to two copies.
20 starting life
Normal win conditions and the London Mulligan.
Open card pool
Every normal Magic card is legal. Un-cards are the only cards excluded.
No ban list
Nothing is banned at launch. Playtesting decides what deserves scrutiny.
Land means Land. Mana rocks, mana dorks, rituals, Treasures, and other nonland mana sources count among your 30 nonland cards.
SPELL
TWIN
IIRESONANCE
Signature mechanic
Resonance
Once each turn, as you cast a spell, you may exile another card with the same name from your hand. If you do, you may spend mana as though it were mana of any color to cast that spell.
Resonance does not reduce the spell’s cost. It trades the second copy for perfect color fixing. You keep tempo, but you lose the twin forever. Convenient, cruel, and beautifully on theme.
Instant deck check
Paste a list. Find the problems.
The checker verifies the structural rules locally in your browser. Nothing is uploaded because not every simple task needs to be fed into a hungry server farm.
II
Your verdict will appear here.
Help shape the format
Playtest. Give feedback. Win prizes.
Run it at the kitchen table, your local game store, or anywhere two people are willing to turn cardboard into a dispute over priority.
Built-in AI guide
Ask Resonance AI.
Get rule explanations, deck structure help, playtest guidance, and LGS event answers without digging through six pages of forum arguments.