Recently, I’ve been addicted to Jump Drive, the latest game from Tom Lehman’s Race for the Galaxy world. This fast-playing card game carries on the central concept of the previous games in the series, which is that players play cards for their printed effects by paying a cost of a number of other cards. Each card can be used as a resource, or for its effect, but not both.
This specific idea goes back to a conversation between Tom Lehman and Richard Borg about how to create a card-game version of Puerto Rico. (The story behind the parallel development of Race for the Galaxy and San Juan is fascinating, and can be read here.) But it’s just one branch of the larger stream of ideas about cards having costs to play — ideas that came to prominence in the mid 90s as part of the emergence of CCGs.
By merging the idea of cards having “casting costs” with the cards themselves being the currency for paying those costs, the design confronts the players with a multilayered challenge. First, there is the question of which combinations of cards work together. Then, there is the question of which can be afforded, which should be discarded, and which should be saved even though they can’t yet be played. For many players these are complex decisions that are also run through with psychological effects like loss aversion and sunk cost fallacies.
Though cards-as-resources is a common way this design pattern manifests itself as a mechanism, it’s not the only one. Some games allow players to use victory points as resource. In this gambit, players forgo points they’ve earned for some ability or action that they believe will earn them more points in the future. Smallworld offers a version of this approach. One pitfall to watch out for is in balancing these exchanges. Designers want to incentivize fun, and getting special abilities is usually a fun aspect of games that have them. If those benefits are not actually worth the VPs they cost, players are disincentivized from taking them. On the other hand, if the abilities are clearly better than the cost, there’s no real decision either, and perhaps the cost is superfluous.
In some games, like 7 Wonders, the convertability of cards to resources functions as a kind of default benefit. While players will typically gain more from playing a card into their tableau or wonder, the ability to discard a card for three gold is an elegant design choices for many reasons. First, it solves the mechanical problem that a player may not be able to purchase any cards from the hand they’ve been given. The discard action addresses that possibility. Second, it expands the possibilities for interfering with other players. You may not want to acquire a card, or may not be able to afford it, but its value to another player may be too high to ignore, such that discarding becomes the best play. Finally, discarding establishes a baseline conversion between actions and VPs. In 7 Wonders, every three gold are worth 1 VP. This equation enables players to compare various moves and reduce them to a value in VPs. By allowing any card to be discarded for 3 gold, and hence, 1 VP, the game is setting the minimum value of an action at 1 VP.
Zooming out even farther, many elements in games can be viewed as resources. Action points are resources. Your turn is a resource. The spaces you’re allowed to build on are resources. Every time we spend a resource, we’re not just obtaining the benefit we’ve spent on, we’re also passing on any other benefit we might have purchased instead. Economists call this “opportunity cost.” The innovation of this design pattern is that your opportunity cost is really explicit: you forgo the opportunity to use the action written on the card. That explicit opportunity cost has a dramatic impact on how players experience the decision they’re forced to make.