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🎮 Deck Simulator (Goldfish Testing)

Practice and test your decks in a solo environment without needing an opponent. The Deck Simulator lets you playtest opening hands, practice sequencing, evaluate mana curves, and see how consistently your deck performs.

What is Goldfish Testing?

Goldfish testing means playing your deck solo. You focus entirely on your deck's performance—how it draws, plays out, and executes its game plan—without worrying about opponent interaction.

Why goldfish test: - Test new deck ideas before playing against real opponents - Practice complex sequencing and play patterns - Evaluate how consistently your deck performs - Check if your mana curve works in practice - Learn your deck's capabilities and weaknesses

Getting Started

Launching the Simulator

  1. Go to Decks
  2. Tap on the deck you want to test
  3. Tap the simulator icon (play icon) in the top bar
  4. The simulator loads your deck and presents an opening hand of 7 cards along with the mulligan prompt

Opening Hand & Mulligans

The simulator uses the London Mulligan rule.

Mulligan Flow

When the simulator starts you see your opening 7 cards and two buttons:

  • Keep – accept the hand and start playing
  • Mulligan – shuffle the hand back and draw a fresh 7

You can mulligan as many times as you like. Each time you mulligan the count increases by one.

Bottoming Cards

After you tap Keep following one or more mulligans, you must place a number of cards on the bottom of your library equal to the number of mulligans taken:

  1. Tap each card you want to send to the bottom (they highlight when selected)
  2. Once you've selected the required number, tap Confirm
  3. Those cards are placed on the bottom of the library and play begins

Game Zones

The simulator organizes cards into standard Magic game zones:

Hand

Cards you've drawn and can play.

Actions: - Tap a card to open the action menu - Drag a card directly onto the battlefield to play it there - Play to battlefield, graveyard, exile, or return to top of library

Battlefield

Cards land on a free-form canvas — drag each card to any position you like. Tapping and Untapping: - Tap any battlefield card to toggle it tapped/untapped - Tapped cards appear rotated - All cards untap automatically at the start of each turn (Next Turn button)

Moving Cards: - Drag cards around the canvas to rearrange them freely. You can drag cards to any of the game zones.

Double-Faced Cards: - A flip icon appears on cards with a back face - Tap it to transform the card - The zone (lands vs. non-lands) updates based on the currently visible face

Library (Deck)

Card count displayed – See how many cards remain

Actions: - Draw one card (draw button) - Reveal – lift the top X cards into the scry/surveil workspace panel (see below) - Search – browse all cards in your library and move any card to hand, battlefield, graveyard, or exile; library shuffles after - Shuffle – randomize the library at any time

Graveyard

View anytime – Tap the graveyard to see all cards in it

Card count displayed – Track graveyard size

Exile

View anytime – Tap exile to see all cards

Card count displayed – Track exile zone size

Reveal / Scry Workspace

The Reveal panel simulates scry, surveil, and similar effects that let you look at the top cards of your library.

Using the Reveal Panel

  1. Tap the eye icon on the library and choose how many cards to reveal
  2. The selected cards lift off the top of the library into a floating panel
  3. Cards in the panel are shown in order — leftmost will be on top when the panel closes
  4. From the panel you can drag individual cards to:
  5. Hand (draw effect)
  6. Battlefield (ramp / cheat into play)
  7. Graveyard (mill / surveil)
  8. Exile
  9. Reorder cards within the panel by dragging them to a new position
  10. Close the panel to return any remaining cards to the top of your library in their current order

Playing a Game

Turn Flow

Next Turn Button: - Advances the turn counter - Automatically untaps all your permanents - Automatically draws one card - Simulates the beginning of a new turn

Manual Actions: - Draw additional cards anytime (for testing) - Play cards from hand - Tap/untap permanents individually - Move cards between zones at any time

Playing Cards from Hand

  1. Tap a card in your hand to open the action menu
  2. Choose an action:
  3. Move to Battlefield – play the card; it lands on the free-form canvas
  4. Move to Graveyard – discard it
  5. Move to Exile – exile it
  6. Move to Deck (Top) – return it to the top of your library
  7. Or simply drag the card onto the battlefield canvas or into another game zone

Lands automatically appear in the lands area; all other card types go to the non-lands area.

Tracking Opponent Life

  • Life counter is displayed at the top of the screen
  • Starts at 20
  • Tap + or − to adjust
  • Use it to track how fast your deck threatens lethal damage

Advanced Features

Library Search (Tutoring / Ramp)

  1. Tap the search icon on the library
  2. Browse all cards remaining in your library
  3. Select a card to move it to hand, battlefield, graveyard, or exile
  4. The library automatically shuffles after the search completes

Shuffle Library

  • Tap the shuffle icon on the library at any time
  • Randomizes your library
  • Use after searches or to test draw variance

Testing Strategies

Test Consistency

Opening Hands: 1. Play through a few turns, then reset 2. See how often you get keepable hands 3. Identify if you need more/fewer lands

Mana Curve: 1. Track which turns you can cast spells 2. Note if you're missing land drops 3. Check if you have too many expensive cards

Draw Quality: 1. See how often you flood (too many lands) 2. See how often you're mana screwed (too few lands) 3. Evaluate if your land count is correct

Practice Sequencing

Test different orders of playing cards to find the optimal line. The free-form battlefield lets you clearly visualize what's in play each turn.

Evaluate Speed

Goldfish Clock: 1. Track which turn you can threaten lethal (20 damage) 2. See if your deck is fast enough for its format 3. Compare different builds

Iterate Deck Builds

  1. Test your current build
  2. Make changes in the Deck Builder
  3. Reopen the simulator and test the new build
  4. Compare performance

Tips for Effective Testing

  • Run multiple games – test at least 5–10 opening hands before drawing conclusions
  • Focus on a specific question per session: e.g. "Do I consistently have a turn 3 play?"
  • Try different mulligans – reset and keep hands you'd otherwise throw back
  • Use the reveal panel to practice scry and surveil decisions
  • Track mental notes – which cards felt good to draw? Which sat in your hand?

Common Use Cases

New Deck Testing

Before playing against opponents: 1. Test the deck's basic functionality 2. Verify the mana base works 3. Practice the deck's game plan 4. Identify obvious issues

Pre-Tournament Practice

Before a tournament: 1. Refresh your memory on sequencing 2. Practice complex turns 3. Test sideboard configurations 4. Build confidence in your deck

Deck Brewing

When building new decks: 1. Test initial concept 2. Iterate on card choices 3. Fine-tune mana base 4. Validate the strategy works

Limitations

What Goldfish Testing Can't Do:

  • No opponent interaction – Can't test against removal, counterspells, or disruption
  • No combat math – Can't test blocking or combat tricks against another board
  • Limited for reactive decks – Control decks need opponents to react to

Resetting and Starting Over

Reset Button

What it does: - Shuffles your original deck - Returns to the opening hand mulligan screen - Resets turn counter to 1 - Resets opponent life to 20 - Clears all zones

When to use: - After finishing a test game - To try a different opening hand or mulligan decision - To test multiple scenarios quickly

Next Steps