I love deduction games.
My first attempt at game design was a deduction game, and I have subsequently designed several others. A couple of these were even published: the solo board game Black Sonata, and the co-operative card game Fallen Angels. I love juggling partial information to narrow down and eventually discover the hidden goal. And I love the tension and release when you make that final guess and flip a card to discover whether you are right or wrong. You get the thrill of discovery either way, even when you are wrong, so for me deduction games are just as much fun when you lose.
Black Sonata, my first deduction game design (image: [user=tikyjo]Tia[/user])
As a child, I knew and played dozens of standard deck card games, especially solitaires, but it wasn’t until my own children were old enough to play that I discovered modern board and card games. I googled “free games for kids” and stumbled into the enormous world of print-and-play (PnP) games on BoardGameGeek (BGG). There were thousands of PnP games on offer, with new ones being designed all the time. I tried some popular ones and loved them. I was hooked.
The Other Hat Trick, the first PnP game I built, a light deduction/memory game and an absolute gem (redesign and photo by [user=lee elektrik]Heiko Günther[/user])
The great thing about the PnP scene is that it allows designers to try new things, take new risks, and combine new ideas without the result needing to have commercial appeal. BGG volunteers run a range of PnP game design contests to encourage new designs and foster collaboration among amateur game designers.
After a while I started having game ideas of my own and entering them in BGG contests. I got useful feedback from others and learned a lot about game design in this way. Some of my contest entries were even picked up and commercially published: Black Sonata and Fallen Angels by Side Room Games and Blorg in the Midwest and Wonder Tales by Button Shy Games.
Fallen Angels, my second deduction game design (image: [user=bgarthwaite]Brian Garthwaite[/user])
Infiltraitors started as an entry in BGG’s 2021 Traditional Deck Game Design Contest. The challenge was to design a game using only a standard deck of cards and, optionally, a handful of generic tokens. I wanted my entry to be a deduction game, of course, so I sat down with a deck of cards and started exploring possible connections between them all. I spread them out, fanned them, flipped them, and arranged them in groups, wondering how you could create an interesting deduction challenge from cards that are so simple and so familiar to almost everybody. My son Liam joined me, and together we brainstormed until a germ of an idea started to form.
It was easy to see how cards can be related, or not, by their suit and value, but the breakthrough came when we realized that cards could be matched by their values being multiples or factors of each other. In that way, a 3 can match a 9 but not a 10, and a Q (12) can match a 4 but not a 5.
Suddenly each card took on a personality of its own. For instance, 2 is a wild party-goer, being buddies with nearly everyone; it matches a lot of other cards but doesn’t tell you very much about any of them. In contrast, 7, J (11), and K (13) are loners, staying home to watch TV while the Q (12) is out with her many friends — but any match with a 7, J, or K tells you exactly what value the matching card has. (See this post for example deductions.) This new way of looking at playing cards could form the basis for a deduction game, but we still needed to figure out how it might fit together. We needed some rules.
Schematic for how different card values are related by being multiples or factors of each other
I have always admired games with simple rules that lead to unexpected interactions and strategies. This is sometimes called “emergent behavior”. One example is Skull (a.k.a, Skull & Roses) in which you simply bid how many rose cards you can turn up without encountering a skull. The rules are simple enough that it has become a popular pub game, with the cards being printed as drink coasters, but you don’t realize until playing how strategic Skull can be in whether to play or bid, what to bid, and how your approach needs to change as the number of cards in each player’s hand dwindles.
I always aspire to create games like this, in which there is more to it than you can guess from simply reading the rules. This was our aim as Liam and I started sketching out and testing rules for hand management, partial information, and co-operative deduction of a pile of unknown cards. After much experimenting and trimming of rules — good game design seems to mostly be about deleting rules — we came up with an interesting standard deck game with deduction and some emergent behavior.
And we thought it was fun, too.
Our original logo for the game when it was entered in the Standard Deck Game Design Contest
Other people also thought it was fun. Infiltraitors was voted Best 2-Player Game and Best 3+ Player Game, while also taking fifth place in Best Overall Game in the 2021 Traditional Deck Game Design Contest.
We were very happy, and that would have been the end of the story except that a few weeks later we received a message from Broadway Toys. Somehow, they had seen Infiltraitors, had played it, and were interested in developing and publishing it. Perhaps they were inspired by the success of Regicide, another standard deck game.
So Liam and I met online with Broadway Toys and their developer Kitty, who would be turning our simple game into something that might appeal to a wider range of players.
Regicide, another game based on a standard deck, by fellow Kiwi designers (image: [user=andyrichdale]Andy Richdale[/user])
Despite having published several games before, I had never worked with a game developer — those previous games had all been ready to go by the time the publishers came along — so this was going to be a new experience for me, and I was very nervous about it. What would they do with our game? Would they rip it apart and turn it into something completely different? Would they retheme it to something I hate? Would they mess with the rules that Liam and I had so painstakingly crafted?
Thankfully, they did none of those things. Kitty came up with cool new ideas for the game, but she brought Liam and I along with her for every step. I was surprised at how respectful and positive the interaction was, and Kitty has taught me a lot about game design in the process.
So what did Broadway Toys and Kitty do? Well, first they expanded the scope of the cards, adding a fifth suit and more values for a richer set of deduction challenges. Then they leaned into the spy theme, fleshing it out with atmospheric art, stylish graphic design, and thematic tokens. Finally, Kitty added a cool campaign structure, with subtly shifting game rules mirroring an action-packed storyline.
Under her development, Infiltraitors has really come to life. Our old standard deck game is still recognizable as its skeleton, but I’m excited about the new muscle that Broadway Toys has brought to Infiltraitors, and I hope that the game will introduce new players to the delights and infuriations of deduction games.
Infiltraitors, as published (image: [user=wankayee]wan ka yee[/user])