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Hello fellow adventurers and welcome to the Nerdlab – Where we transform our gaming passion into incredible game designs and learn how to nerd like a boss. 
My name is Marvin and I am an ambitious game designer on my quest to develop a co-operative fantasy card game.
For this podcast, my vision is to take you with me on this exciting journey. Together we will explore the secrets of different game mechanics and reach the next level as a game designer.

Today’s show is about a “skeleton”. Before you panic and start looking for your weapons right now, be calm. We’re not talking about undead. We are talking about a design skeleton. Some form of blueprint for your game design.   

If you are able to execute the process of creating a “design skeleton” from front to back, then you are well on the way to creating a good game. I first saw this process model in an article by Mark Rosewater, Lead Designer of Magic, and I have been using it for all my designs ever since. Today I will show you how to create a design skeleton for your game in 7 steps. As an example I will use the creation of a Magic the Gathering Set today.

Definition: What is a design skeleton?

Some form of undead version of your game? 

  • A design skeleton is a rough and preliminary plan of how your set of cards (or other components) will look like.  
  • It is a blueprint for your future work from a meta perspective. 
  • The purpose of a design skeleton is to identify what kind of cards you will need in your set without describing those cards in detail. 
  • In the end, the design skeleton is a tool that helps you to get a big picture of all the aspects you want to put into your set of cards. It helps to start figuring out what the set is going to need design-wise both on color or faction level and card level.
  • Because a design skeleton spells out what is needed for each slot, it’s very easy to just want to fill it in and be done with it, but that’s not what a design skeleton is for. A design skeleton is a tool a designer uses to give him a general sense of what the overall set is going to look like. I compare it to a sketch because it’s used in much the same way an artist uses a sketch.


First Step: Preliminary thoughts

Before we can actually create our “Design Skeleton”, we need to be clear about a few basic things:

  • How do cards differ
    • Alliances, colors, card types
  • How many cards do I need in total
  • How many cards do I need per distinguishing criterion 


This does not mean that all these questions have to be finally answered, but you have to have at least a rough idea of what they are. Otherwise, it probably makes no sense to create a “Design Skeleton”. In terms of timing, I would say you create a Design Skeleton after you have an idea of the scope of the game. That means after you have thought about the goal of the game, the required components, constraints and your gameplay loop.  But before you start with the actual card design.

Second Step: Definition of Card Slots 

The second step when creating a design skeleton is to set up a spreadsheet and create one line per card slot. 

But what is a card slot you may ask? That is actually something you need to create exactly now if you don’t have it already. 

  • For existing games, people are using card names and titles to refer to a card. That works because printed cards are constants. But during the design process and playtesting cards can change rapidly. And I do not only mean simple values on cards that change from 1 to 2, but also entire cards. Also, the theme and title of your card could change often so you might not be able to determine which card this final card represented in the beginning of your design. Card Slots are typically way more consistent. But they can also change of course.  
  • But what is a card slot. It all comes down to your distinguishing factors and the questions we already asked ourselves during step 1. Let’s take Magic as an example:
  • Magic has quite a few design constraints and distinguishing factors. The two most important ones for designing a new set are rarity and color. In Magic a typical set as a fixed amount of commons, uncommons, rares and mythics. Since Magic sets are typically almost symmetrical when it comes to color distribution that means that each color has a fixed amount of slots per rarity. In the actual magic set “Theros Beyond Death” are 108 commons. 19 or 20 per color + some artifacts and lands. 
  • If you then add additional distinguishing factors like card type you get very particular slots. For example, you need 10 to 12 creatures in the common slot per color. That means you already have these slots fixed. Then they probably want some instant tricks per color, some removal, some enchantments and so on. At the end of these considerations, you end up with a list of card slots. But where do you start if you don’t have constraints like x amount of cards per faction and best practices like 10 creatures per color? Do your research and look how other games are doing it. Make assumptions and use math to create constraints and rules of thumb. Consider probabilities. How likely will a player see a card of tpye x when he draws y cards? Is this chance enough or do not?  
  • Once you have your rule of thumbs write them down and work on your Card Slots. 

Unique Identifier per Card Slot

What also belongs to the second step is give each slot a unique identifier. Magic uses the term Card Code for that. 

In Magic this code is alphanumeric:

First Letter determines rarity: 

  • C – common
  • U – uncommon
  • R – rare
  • M – mythic rare
  • L – land (This refers only to basic lands; all other lands fit into one of the above four rarities.)
  • T – token
  • S – special

Second letter represents the card frame which is similar but not exactly the color of the card: 

  • W – white
  • U – blue
  • B – black
  • R – red
  • G – green
  • Z – multicolor
  • X – split cards (That’s split cards that aren’t monocolored; the mono-red ones in Planar Chaos, for example, just used R.)
  • A – artifact (This is for traditional colorless artifacts; colored artifacts, except for Transguild Courier and Reaper King, use the appropriate color code.)
  • L – land

Two-Digit Numbers represent a consecutive number per slot type. If they have 20 green common slots those slots would get the codes C – for common – G for green – and then 01 to 20 for those 20 slots. Then the same happens for all the other colors and other rarities. 

Magic R&D uses those Two-Digit Slot also for some other information. If they remove a card from the set but are not sure it might not get back in, it gets assigned the number 99. If they are working on a card but it is not yet assigned to a slot it gets assigned the number 88. There are more number codes they use to assign cards to team members working on them, to add notes and so on. But the main purpose really is to retain a list of slots and assign cards to that slots. 

Third Step: How many cards for your most important card type

Once you have your rough slots, you need to go into a little more detail. First of all, think about which card types are most important for the robustness of your game. In the case of Magic, these are definitely creatures. In the case of my drafting game, these are the Heroes. 

  • That means the first thing Magic designers do when they design a new set is to think about how many creatures they want in that set. The answer is often something around 50% for a regular set and the common slot. 
  • But in Magic this number is not equal for all colors. White and green tend to have more creatures than blue, black or red. The reason for this is the different playstyle of each color. That means when you have 100 slots available and think you need 50% creatures for your game to work best, you can distribute 50 creatures to the different colors. In Magic this would be 10 per color. But then you could argue that white is the color that goes wide with creatures and take one creature away from blue to add it to white and so on. At the end a set might end up with 7 blue creatures but 10 white creatures and so on. 
  • Once you have assigned your most important card type to the slots you add a new column to your spreadsheet and put that type in. That means the first 10 white common slots would be assigned to “type” creature but only 7 blue slots would be assigned at that point.
  • If you also have factions in your game and the goal that these factions have different playstyles because they utilize different card types more or less, this is the perfect time to consider this in your design skeleton.  

Fourth Step: Super rough card design of your most important card type

At that point of the skeleton, it can already make sense to create a super rough card design. By that I mean two things. Core Values (in Magic Power and Toughness) and Keywords. I am pretty sure that one blue Card Slot in Magic is always – Blue common creature 2/2 flying. The set specific twist comes later. For example by adding a set specific keyword or additional unique rules text. But at that point you don’t even need to be that specific. It could be enough to distinguish between small – medium – large creatures. Or by distinguishing between tank – damage – dealer – healer or whatever is appropriate for your game. The goal is to bring your color or faction identity to life. Step by Step. And you can do that best by getting more and more specific which each step. 

Fifth Step: Adding slots for the other Card Types

Once you have a rough idea of your most important card type you can fill up the rest of the slots with the other card types. But think about your choices and create assumptions and rules again. Here are some example rules of Magic. Each color gets an aura, but global enchantments can typically not be found in the common slot. All colors gain instants but white and blue get more than the rest. All colors get sorceries but black and green tend to have more than the rest. Artifacts tend to be utility cards. 

While you are filling the remaining card slots you will probably also make changes to the existing slots you already entered. Let’s say you realize you do not have enough slots for instants in a color, but you want to have that surprise moment you could add the keyword flash to one creature to make up for that. 

“This demonstrates the point of the skeleton. The skeleton isn’t there to lock the designer in but to make the designer aware of what things they need to allocate. When something isn’t working, the designer then has to re-adjust the skeleton to get what they need.” 

Sixth Step: Faction Specific effects 

In this step you go a bit deeper on your factions and how you want them to play out. If we stick with Magic the gathering, this would be the step in which you add the typical effects colors are famous for. Green gets a +3+3 pump spell at instant speed, blue gets a counter spell, red gets some form of lightning bolt, black some form of destroy effect and so on. But this is not only one card, this is typically an entire set of abilities and card effects. White gets something with lifegain, enchantment removal, and creature removal (often as enchantment), a combat trick and a spell that pumps the entire team. Sounds familiar to any magic set. Yes because it is. It is a proven structure that is reused over and over again with little twists and new flavor. And there is nothing wrong with it. As long as it does not feel repetitive for the players. If we design a new game we, unfortunately, don’t have this recipe for success. Nevertheless, I think it is the best way to distinguish between the different playstyles in your game and consider them at this state of the skeleton. 

Seventh Step: Adding set specific effects and mechanics you want to test 

Magic also adds their set-specific keywords and effects at that point of time. 

Typically the most common design issue is having too much to fit in. Too many card types. Too many keywords, too many effects, etc. Think about adding some of your desired effects on other card types. If you don’t have space for another sorcery or instant effect, add it as an enter the battlefield effect or on death effect on one of your creatures. 

When you work on your skeleton you will be forced to think about things like how often do I want to use this keyword. In which color do I use this keyword and what flavor and play type comes with it. This is the birds-eye view you can get from a good design skeleton. If you are working on individual cards, or spreadsheets with all the information we can sometimes lose the ability to see the big picture because we are too much in the details. 

That’s why I often go back to my design skeleton and see how my set of cards is coming together and what is missing. Treat the design skeleton as a starting point but also as a living document that helps you to see the big picture.