When I was about nine years old, I excitedly challenged my dad to a game of chess. I had just learned about the 4-move mate, which seemed like magic to me. My dad was a strong chess player, and he never took anything off of his fastball. I was excited to deliver a 4-move knockout blow against him, but needless to say, things didn’t work out that way. My father saw my plan a good three moves in advance and casually countered it, quickly cornered my queen, took her, and left me in tears. I didn’t understand why my clever plan fell apart. My dad, explained, not entirely unsympathetically, “no plan survives first contact with the enemy.”
Thinking ahead and responding to opponents and events is a foundational skill in gaming of every kind. What goes into it? What types of thinking do we engage in when we think ahead? How can a designer take advantage of how people plan to create better gaming experiences?
Abstract games are great models for exploring thinking ahead. Most abstract games are perfect information games, with no random events or hidden knowledge for us to account for in studying how players make decisions. Whether you’re playing Onitama or Hive, you always know what you and your opponent can do. In these games, when we look ahead and see how an opponent might respond to a move, we look down what’s called a “forcing line,” a move that generates a series of predictable responses because failure to respond in the way being “forced” would lead to an even greater loss for the player. A strong player will seek a move that sets off a forcing line whose end result yields him some benefit or advantage in the game.
The “forcing line” is a critical concept. It allows players to exert control over their opponents, especially in abstract games. In other kinds of hobby board games, moves that attempt to dictate the play of our opponents aren’t quite as forceful. My choice to draft military in 7 Wonders gives my neighbors additional incentive to draft military too, but they can ignore my military advances and focus on making up the difference in civic buildings. My moves to monopolize sciences, on the other hand, forces a response, or the strength of science’s exponential scoring will likely lead to my victory.
Even in low-interaction Euros, we can see forcing lines in play. Perhaps the clearest version is an I-cut-you-choose mechanism, in which one player is literally defining the options the other player may take. Games with variable ending conditions can sometimes allow a player to rush towards the endgame, which is a kind of forcing line too.
Forcing lines can have some downsides. In Chess, for example, even relatively inexperienced players can identify hopeless endgame positions, like queen and king vs king. In these positions, a sequence of moves will inevitably lead to checkmate. Novices will play these positions out to learn how to manage them, but more experienced players will resign these positions, or even significantly more complex positions, because there’s no need to play them out. The end is clear, and is forced, and playing out the string is meaningless. A modern game design strives to ensure that there is no leftover meaningless play dangling off the edge of a game design.
Another downside of forcing lines is the risk that they run too long. Bridge and other trick-takers can sometimes have five or more tricks that are entirely forced, with players making no real choices during that stretch. Again, modern designers seek to limit these ‘dead’ stretches through clever design, and focus the experience on the more interesting, decision-rich moments of play.
Designers should consider how to use forcing lines in their designs carefully. Too much forcing removes agency, can lead to snowballs, or even, surprisingly, to stale positions where players are forced into repeating patterns. But at heart forcing lines are about giving players opportunities to plan ahead, to put opponents on the horns of difficult dilemmas, and to set up clever multi-move plays. A forcing line is a powerful tool in a designers toolkit.