When to Keep or Mulligan in Legacy: A Decision Tree

Legacy rewards powerful opening hands, but power alone does not make a hand keepable. A seven-card hand can contain Force of Will, Brainstorm, and several lands yet fail to advance your plan. A six-card hand can look less impressive while offering the exact mana, interaction, and pressure required for the matchup.

The London mulligan gives every player more control over this decision, but it also creates more opportunities to misjudge a hand. The goal is not to find a perfect seven. It is to identify a functional hand that executes a realistic plan before the opponent’s strategy becomes overwhelming.

A useful mulligan decision tree begins with your deck’s priorities, then considers mana, action, interaction, and the role you expect to play. Applying the same sequence every game makes your choices more consistent and helps you separate genuine risk from ordinary variance.

Start with your deck’s primary plan

Before evaluating individual cards, identify what your deck must accomplish in the first few turns. Delver decks usually need a stable mana base, an early threat or cantrip, and enough disruption to protect their initiative. Reanimator needs access to a reanimation spell, a creature, and a reliable way to place that creature in the graveyard. A control deck may value lands and selection more highly because its cards become stronger as the game develops.

A hand should be judged against the deck’s actual plan rather than against an abstract idea of card quality. A hand containing three individually strong cards may still be a mulligan if it has no source of mana or no way to deploy them. Conversely, a narrow hand can be excellent when it has a high-probability route to victory or a strong answer to the opponent’s expected opening.

Matchup knowledge changes these standards. A slow seven may be acceptable against another fair deck, while the same hand may be too passive against Storm or Initiative. Your pregame sideboarding and scouting should therefore include opening-hand priorities, not only cards to bring in or remove.

Check mana, action, and interaction

The first practical question is whether the hand can produce mana. Count colored sources, not just lands. A hand with Ancient Tomb, Wasteland, and a blue spell may technically contain lands but still be unable to cast its important cards. Similarly, a hand with multiple fetchlands may need a clear understanding of which dual land or basic land it can access without creating a vulnerability to Wasteland.

Next, ask whether the hand does something meaningful. “Action” can mean a threat, a cantrip, a tutor, a lock piece, or a proactive combo sequence. Hands that contain only reactive cards often become weaker when the opponent refuses to play into them. Hands with only expensive spells are also dangerous unless the deck is designed to make that mana quickly.

Interaction should be evaluated by timing and coverage. Force of Will is valuable against a turn-one combo spell, but it may be a poor substitute for a real development plan. Swords to Plowshares answers creatures efficiently, yet it does little when the opponent’s critical card is a noncreature permanent. A keep usually needs interaction that matters in the matchup and a way to use the extra turns that interaction creates.

Follow a decision tree before keeping

Use this sequence whenever you draw an opening hand. It is quick enough for tournament play and detailed enough to expose hands that feel attractive only because they contain familiar cards.

Decision point Keep signal Mulligan signal
Mana Two or more useful sources, or a clear one-land plan No mana, color problems, or fragile acceleration
Early action A threat, cantrip, tutor, combo piece, or engine Seven cards that only react or wait
Matchup role Cards support your likely role as aggressor, controller, or combo player Hand fights a different kind of game
Interaction Relevant answer with a reasonable way to deploy it Dead cards or protection without a plan
Resilience Can recover from one disruption spell Folds to a single common answer
Mulligan value Six-card version can improve meaningfully Hand is functional but low-impact in a favorable matchup

If the hand fails the mana test, mulligan immediately unless the deck has a deliberate one-land strategy and the hand contains enough selection to find the next source. If it passes, determine whether it has a line for the first two turns. A hand that cannot cast a spell, create pressure, or establish a meaningful engine by then deserves serious suspicion.

After that, compare the hand with the opponent’s likely plan. Against a fast combo deck, ask whether you can interact before the combo turn. Against a creature deck, ask whether your first answer arrives before you lose too much life or board control. Against a slow control deck, prioritize mana development and card quality, since an opening hand with no pressure may still be strong if it generates superior resources.

Adjust for archetype and matchup

Tempo decks generally keep hands with a low curve, efficient mana, and a threat or cantrip. A seven containing Daze and Force of Will but no clock may be acceptable only when the matchup makes early disruption especially important. If the hand cannot turn temporary interaction into pressure, the opponent may simply wait until those cards lose value.

Combo decks should evaluate a hand by its probability of presenting a protected line, not by how many combo pieces it contains. A hand with multiple discard spells and no payoff may be too slow, while a hand with a complete line and one form of protection can be excellent even if it has fewer flexible cards. Do not overvalue speculative cantrips when the deck needs to act immediately.

Prison and artifact strategies often accept hands that are less conventionally balanced because a single permanent can dominate the game. Still, the hand must cast that permanent at a useful time. Lands, fast mana, and a lock piece form a coherent keep; several lock pieces without acceleration usually do not.

Land-based strategies provide a good example of why matchup context matters. A hand with Exploration, Life from the Loam, or Urza’s Saga may be strong when it can assemble a resilient engine, but it can be too slow against fast combo. The Urza’s Saga analysis shows how a single land can serve as both development and threat, which changes the value of otherwise modest opening hands.

Recognize hands that look better than they are

A common trap is the “all interaction” hand: several counterspells, removal spells, or discard effects with no proactive route. Such a hand can win when the opponent supplies threats one at a time, but it may lose to a single must-answer permanent, a topdecked engine, or an opponent who simply declines to trade resources.

Another trap is the “perfect curve” hand with the wrong colors. Players often keep because the cards fit a textbook sequence, ignoring that a fetchland, basic, or dual land cannot cast the sequence under pressure. Write out the first three turns mentally, including likely Wasteland targets and opposing disruption.

A third trap is the speculative cantrip hand. Brainstorm, Ponder, and Preordain improve many hands, but selection is not the same as action. Keeping a hand that depends on one cantrip finding exactly one missing card is reasonable only when the deck has enough copies, the matchup allows time, and the initial mana is secure.

Build a repeatable mulligan habit

The best way to improve is to record decisions rather than relying on memory. After a league or tournament round, note the hand, matchup, keep or mulligan choice, and the first few turns. Then ask whether the hand’s failure came from bad luck or from a flawed evaluation. This separates a correct keep that missed from a hand that was never structurally sound.

Use the following checks before submitting your opening hand:

A consistent process also makes mulligans less emotional. Losing a card is a real cost, but keeping a hand that cannot function often creates an even larger disadvantage. The goal is to maximize the chance of executing a coherent plan, not to preserve every card in the opening seven.

The Legacy community offers a broad range of decklists, tournament coverage, and strategic discussion for testing these judgments in context. Reviewing the Legacy articles can help connect abstract mulligan principles with actual archetypes and metagames.

Turn better keeps into better results

Mulligan decisions become easier when your deck has clear priorities. Know which hands are automatic keeps, which are matchup-dependent, and which require an unusually favorable draw. Test post-board games separately, since additional removal, hate pieces, and flexible answers can change what counts as a functional opener.

Bring this decision tree to your next Legacy event and apply it before every game: mana first, action second, role third, and resilience last. With repetition, you will spend less time asking whether a hand “feels good” and more time identifying whether it actually performs the job your deck needs.