This is something you also see a lot with specific card mechanics. Looking at Magic: The Gathering for example, we see that a lot of card mechanics explicitly encourage you to play with certain other cards. For example, affinity for artifacts (on cards like Frogmite) wants you fill your deck with cheap artifacts, whereas slivers (like Muscle Sliver) give bonuses to your other slivers, meaning that the value of each one goes up the more of them you have in play. But this type of synergy doesn’t always have to be so explicit. Double strike, for example, is a very simple mechanic that lets your creature hit twice every time it attacks. Having one card with double strike in your deck doesn’t obviously make you want to put more of them in your deck – except it does want you to play spells that can increase the power of your creatures (like Giant Growth), as the impact of those spells essentially doubles if you cast them on a double strike creature. And if you’re playing a card like Giant Growth in your deck, that in turn makes you want to put more double strike creatures in your deck. You see these types of ‘value cycles’ fairly commonly in card games.

And while we’re talking about Magic, it’s worth mentioning one really huge innovation that game brought to this space – a faction system (or more specifically in Magic, the colour pie). In Magic, the way this works is that there are 5 colours of mana, and most cards require you to spend a specific colour of mana to use them. Mana is only generated by certain cards (mostly lands) and most of those can only generate a limited number of colours. There is a constant tension when playing and when building your deck between how many different cards you want access to, and how reliably you want to be able to use them. In effect, this means that the value of your cards is always going to be dependent on how many other cards of the same colour you are playing.

Other games have since found new and innovative ways to implement a faction system. One I’m particularly fond of is Ascension’s. Unlike Magic, Ascension doesn’t use a faction system to limit which cards you can and can’t play. Rather, it uses its factions to subtly push you towards different strategies, typically meaning that acquiring one card of a given faction in a game makes you more likely to want to acquire other cards of the same faction. Sometimes this is explicit – a lot of Lifebound cards like Runic Lycanthrope give you a reward when you play another card of the same faction – and sometimes this is more subtle – many Mechana cards reward you for acquiring and playing constructs (a card type), and the more constructs you acquire, the more valuable other Mechana cards are going to become to you.

If you’re designing a game and finding that the value of cards aren’t fluctuating enough, a faction system can be a good way to fix this. A good example of this comes from my own game, Underleague (which, if all things go to plan, will be launching on Kickstarter this year). During the game, each player controls 3 creature cards in their ‘stable’, and to begin the game they create a starting stable by looking at the top 3 cards of their creature deck and choosing one of them – and then repeating this twice.

Early playtests, however, showed that this system was problematic. As the game goes on, the value of creatures fluctuates based on the strategy that a player has committed to – but at the start of the game, the player has had virtually no space to explore different strategies and to commit to one. And this meant that the cards that seemed to be the weakest in a vacuum would almost never appear in a player’s starting stable, because a player would always have 2 ‘better’ options to pick from.

I realised that this problem could be mitigated if there were a way to more explicitly make the value of the second and third creatures you selected at this stage of the game dependent on the creatures you had already selected. The best way to do this, it turned out, was through a simple faction system. As I was trying to avoid adding much more complexity to the game, I made each creature a member of one of three factions (‘beasts’, ‘constructs’ and ‘spirits’) and gave the player a small bonus (an extra card they could draw) each turn if all of 3 of their creatures belonged to the same faction. This immediately solved the issue I was having; suddenly, if a player had chosen a beast card as the first creature for their stable, they would often (but not always) be willing to choose a beast as their second creature even if it was ‘objectively’ slightly weaker than the other two options available to them, because they knew that the extra card a turn would make up for it. As the game developed, I was also able to weave in different mechanical themes to the three different factions, further promoting this idea of conditional value; beasts, for example, are more likely than others to reward you when you win fights with them, which in turn means that if your stable contains 3 beast creatures, you become more interested in strategy cards (the other type of card in the game) that increase your odds of winning a fight.

If you’re a working on a game and finding that some of the cards aren’t being played as much as you’d like, the solution isn’t always to buff the weaker cards or nerf the stronger ones. Sometimes, it’s symptomatic of the fact that your game system itself isn’t doing enough to make the cards’ values conditional – and a faction system can often be a way to remedy this.

Second source of conditionality: what are my opponents doing in the game?

The problem with the first source of conditionality, however, is that eventually it becomes stale. Once you’ve built a deck and played it enough times, the interactions between cards all become rote; after a few plays, players for the most part will be able to mentally shortcut a lot of the value-judgement created by the interactions of their own cards. Everything becomes predictable.

But opponents aren’t predictable. In my experience, the act of constantly re-evaluating your cards – and your deckbuilding choices – based on the actions of your opponents is one of the most consistently rewarding elements of this genre of game.

Going back to the earlier point about different strategies; it is not only important that a game can support different strategies, but also that those strategies interact with each other meaningfully. A great illustration of how this creates conditional value can be seen in the classic MTG strategy article, ‘Who’s the Beatdown?’. In short, if two players are both playing aggressively, then the player with the deck that can end the game the quickest will win. The only way the player with the slower deck will win will be if they realise that they need to readjust the value of their cards; cards that can help them prolong the game and survive their opponent’s early onslaught become more valuable, so they need to prioritise them over playing their own more aggressive cards.

You also see this sort of conditionality a lot in any game where players are fighting over shared resources – for example, in games that have a deckbuilding or drafting element. In Ascension, for example, you can get closer to victory by purchasing heroes or defeating monsters, all of which occupy a central row accessible to all players. So if all of your opponents are focusing on defeating monsters, the value of that strategy goes down – as any powerful monsters (like Xeron, Duke of Lies) that get added to the central row will likely be vanquished before your turn comes around.