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Opening Hand Simulator

The Test tab runs deterministic Monte Carlo samples against the current main deck. It helps identify why opening hands fail, how mulligans affect final hand quality, and which deck-composition changes are most likely to improve consistency.

Simulation Inputs

  • Iterations controls the sample count used by the baseline and every what-if scenario. Values are limited to 10–9,999 to keep browser-side analysis responsive.
  • Keepable Hand combines the land range with every added tag minimum. All conditions must be true for the opening seven to be keepable. Counts are limited to the seven-card opening-hand size, and the minimum land count must remain below the maximum.
  • Mulligan Settings control the maximum number of paid London mulligans, the optional multiplayer free mulligan, and the turn through which natural draws are analyzed.
  • Draw Goals track lands, tags, or a specific deck card by a chosen turn. These goals do not affect whether an opening hand is keepable.

Commander and Brawl decks default to one free mulligan. Other formats default to no free mulligan, and the setting can always be changed.

Results

The headline Opening Keepable % is the chance that the initial seven-card hand satisfies every keep condition. Mulligan Success is separate: it is the chance that an optimized London mulligan finds a qualifying final hand before the configured limit.

The dashboard also reports:

  • Exclusive reasons that opening hands failed.
  • Exact opening-land and configured-tag count distributions.
  • Average mulligans, average final hand size, forced keeps, and final hand-size distribution.
  • Chances of making each land drop on the play and on the draw.
  • Play/draw success rates for every configured draw goal.
  • Size-preserving what-if estimates for lands and configured keepable-hand tags.
  • The final sampled hand, using the same interactive card previews as the rest of the app.

Modeling Assumptions

Draw analysis uses natural draws only. It does not assume ramp, tutors, scrying, special draw effects, or gameplay decisions. MDFCs use the simulator’s normal type-line land classification.

What-if results are composition estimates, not literal deck edits or legality recommendations. Each scenario keeps the library size fixed by swapping virtual matching and nonmatching slots; the saved deck is never changed. The displayed impact score equally weights the change in overall keepability and the change in the adjusted requirement’s opening-hand probability; both component deltas remain visible beside the chart.