TLDR

The goal of wubrg.gg is to build a deck-building tool that goes beyond what a hypergeometric calculator can offer. It runs a Monte Carlo simulation of 1,000+ of games to estimate how well you will be able to cast your spells.

Getting started

Fill in the simulation settings on the left. Then, paste your deck list in the provided text area. The deck list should include a "Deck" section (which will be simulated) and a "Sideboard" section (which will be ignored). Finally, click the blue “Run” button in the header (upper right) to see the results.

To get your deck list from 17lands, click on the "Deck Export" button from the deck view and select "Copy as plain text" and then paste it here.

How to use this tool

Start with your best guess at how you want to build your deck. Then run the simulation and go through the key statistics and visualizations. The dead spells and spells cast per turn statistics are key. Compare how your deck is performing on those metrics to the trophy decks (of your color).

Then, inspect the dead spells by missing color chart to see if you are missing a particular color more than others. If so, try adjusting your land base to better align with your color needs. Re-run the simulation and see if your summary statistics improve.

If not, you may want to consider removing a splash, adding more fixing, or adjusting your curve.

How the simulation works

The simulation runs many iterations of a simplified game scenario. For each simulation:

1. Your deck is parsed and each card is converted to its mana requirements and production capabilities.
2. We then play out each turn:
   • One land is chosen from your hand that best increases your potential mana usage for that turn (or if none help, we play the land that looks most likely to help cast spells in hand in the future).
   • Spells that produce future mana are cast first (if castable), then creatures, then other permanents, then interaction and card draw. When more than one spell of a give type is available (e.g., three creatures) we choose the combination that maximizes total mana usage.
3. For each card in your hand, if it could not be cast on that turn (on its own, ignoring other spells), it is considered “dead” for that turn. We separately log whether it is missing any particular color by checking if substituting a single land in play with a basic of a certain color would fix the shortfall.
4. We track how long each spell in the opening hand waited before it was eventually cast (or if it never got cast), providing data for the delay chart. We also note if at least one nonland spell was cast by turn 3.

Statistics are computed for each turn and each simulation, and the results are aggregated and presented as key statistics and various charts. You can also follow along with a sample of individual simulation passes in the “Simulation audit”. This can be helpful to better understand what is actually happening in the simulation.

Key Assumptions

• Fixed Turn Structure: We simulate a fixed number of turns with random draws.
• One Land per Turn: We always attempt to play exactly one land each turn, but pick which one based on the best immediate or fallback priority.
• Mana Use Priority: We greedily prioritize spells that will produce mana on future turns, then creaturs, then other permanents, then interaction and card draw.
• Delayed Interaction: We delay casting any interaction until the second turn (you can control this in advanced settings) as it is unlikely there is anything to interact with on the board on the first turn.
• No Instant-Speed Complexity: We assume everything is cast in the main phase with no holding up spells for an opponent’s turn.
• Affinity Adjustments: We reduce colorless cost by a fixed rate each turn for affinity spells, without an actual board-based count of artifacts.

Simplification of Real MTG Games

This simulation focuses solely on mana availability and the ability to cast spells. It does not capture many of the complexities of real Magic. For example:

• It does not simulate card draw, tutoring, graveyard synergies, exhaust abilities, etc.
• It does not account for "Verge" lands ability to produce a second color of mana only if another is in play (we assume it can always cast for both).
• We aren't simulating anything related to combat or life totals (this is just about greedy use of mana).
• It doesn't consider the value of holding onto a card for a future turn.
• We aren't keeping track of any affinity cost reductions tied to actual board state. Instead, we let you specify a fixed rate at which colorless cost drop for affinity cards over time.
• Cards that indirectly affect the costing cast of other cards (outside of basic affinity) such as Voyager Quickwelder or Racer's Scorecard are not accounted for.
• Lands like night market are not fixed in color when they are cast, but remain flexible in future turns. This is a simplification.
• Tubrid cards (those with costs that can optionally be 2 generic or 1 colored mana) are treated as though they can only be cost for their colored mana cost or for all generic mana.
• In general, for mana rocks and cards that tutor for lands, we consider them tapped on the turn they enter if that is reasonable (e.g., summoning sickness), but then treat them as being able to tap for mana of the requisite color indefinitely.

So, in general, think about this as the most optimistic scenario for spending your mana.

What Is Captured

The following are core elements of the game that we do account for in the simulation:

• Basic lands, dual lands, and other land types that can be tapped for multiple colors.
• Spells that can be cast and then produce mana in future turns.
• Lands that enter tapped, and so cannot be utilized on the turn they are drawn.
• Spells that can be cast for alternative costs such as cycling or other condition-based reduced costs.
• Arena Bo1 hand smoothing.
• Affinity costs drop colorless casting costs for affinity cards one mana per N turns not going below zero. This effectively reduces the colorless portion by floor(turn / drop_amount) each turn, not going below zero.