Luke Crane and David Petersen’s Mouse Guard RPG is one of my favourite role-playing games and based on one of my favourite comic book series. One of the central mechanics – the GM and player turns – are both clever and contentious. This article expands on discussion of these systems on the #burningwheel IRC channel.

For those unfamiliar with Mouse Guard the GM and player turns split a game into two related but structurally different pieces: a turn where the narrative is lead by the GM and turn where the narrative is lead by the players. These turns are relatively coarse: a short mission or scenario may consist of only one GM’s turn and one players’ turn (longer missions may contain more). Furthermore these turns are linked: players earn checks within the GM’s turn that they can spend within the players turn in exchange for action.

First, the contentious point: Some readers – and novice players – assume that the GM’s turn is (to use a loaded term) railroading. They feel that because the GM has a firm hand on the tiller of the GM’s turn that the players have no input and are merely along for the riding.

The GM’s turn should instead be considered nearly identical to that of a typical (non-sandboxed) RPG where the GM provides the majority of the direction. Where it differs is that the GM is restricted in terms of what she is allowed to do during this phase. In practise Mouse Guard is like a typical game except that it has a players’ turn (and it’s relationship to the GM‘s turn).

The restrictions placed on the GM for how she runs her turn are important. They ensure that the, often disadvantaged, player characters have some framework within which they can marshall the limited resources they have available, and when it might be wise to earn a check (by impeding themselves).

A mission is comprised of challenges. The GM is advised to prepare on challenge of each hazard type from mice, animals, weather, and wilderness. Two of these challenges form the core of the mission, with the other two held in reserve (see page 61, Pick Two).

The outcome of any challenge is one of three things: success, success with conditions (such as injury, hunger, anger etc), or a twist. A twist results in a new challenge to overcome. This means that no matter what happens the players experience some sort of forward progress.

The GM will often choose a challenge from the two reserved for a twist, but is not obligated to. Alternately she may choose to introduce a twist that simply makes the current situation worse. Like any game, the GM prepares challenges with some concept of how the players may tackle it. Likewise when the players surprise her, the GM may improvise a suitable follow up challenge rather than stick with a reserve.

The rules for twists include an important restriction: The GM is not allowed to make the players face for the same situation again. A worsened variant of the situation is fine; the stakes are higher. In other words, the results of a test are binding.

For instance: the patrol tries, and fails, to put out a fire started by an arsonist (a survivalist test). The GM them introduces a twist: the fire has spread to neighbouring buildings and is threatening to engulf the town!. Now the patrol faces an orator test to marshall the town mice to fight the fire. Same challenge, different situation. The players cannot roll again to fight the fire at its initial scope.

Players should be pushed into situations where they are required to make hard choices. For example:

Imagine this: It's raining hard. A rivulet has formed outside Elmoss, blocking the main road. This rivulet is rising fast. A grain shipment for the town is stuck on the far side, in danger of being swept away. Your cousin, another guardmouse, is trapped on a branch in the middle of the rivulet. You only have time to save one before the other is swept away. What do you do?

Touch decisions and constant pressure is what the GM's turn is about. Mechanically, the clearest expression of this is checks. In order for the players to benefit from the players’ turn they need to earn checks during the GM’s turn. Checks are earned by the character’s hindering themselves. Do you do your best to succeed at the mission, but not be able to fulfil your own goals, or do you potentially sacrifice the mission to get your own way.

This balancing act would not work if the characters were not under constant pressure during the GM’s turn. Every roll must matter.

In contrast, the players’ turn is something not found in many games: a section of play that is both bounded but player directed. This could be considered sandbox play. As mentioned previously how much the players can achieve depends on how many checks they have to spend. Each check can be spent on a single test. Once again the players’ priorities are challenged. Between recovering from conditions, chasing personal goals (such as the Goal and Belief written on the character sheet), and preparing for the GM’s turn ahead, they will need to spend their checks wisely.

Players’ turns are introduced at specific points: when the mission is completed (successfully or unsuccessfully), when the patrol reaches a safe haven, or during downtime on longer missions. This ensures that the points within the game where the players would expect to have more freedom, they do.

For players expecting a more traditional fantasy game structure, but merely dressed up in mice verses the wild, the structural expectations of this game are likely to be jarring. Mouse Guard has more in common with a thriller or horror game than a classic fantasy. The patrol has a job to do, and they do not have freedom to explore casually and on their own terms.

A final point on the purely structural aspects of Mouse Guard RPG games. The alternation of GM’s turn and players‘ turn creates a rhythm to play. The suggested two to four challenges per GM’s turn where the heat is on, is countered by a more relaxed player‘ turn of approximately similar length – once the players are comfortable with earning checks anyway. The relaxed phase makes the following pressured phase more thrilling. Conversely, the pressured phase makes what respite and recovery the patrol finds during the relaxed phase more rewarding.

With all this in mind, the most important question is does this support the premise of the game? Mouse Guard is revolves on the statement “It matters not what we fight, but what we fight for” uttered by Kenzie early on in the first comic.

What the characters fight for is embodied in their beliefs and goals that are written on their character sheets. The difference between a successful and unsuccessful game of Mouse Guard is, in my opinion, derived from how theses qualities are challenged throughout the course of the game.

This intersection between mission, challenges, and the mice of the patrol forms the ongoing situation (pages 62–64). The mission and challenges alone merely form a spine for the game, and thus the story, to hang off. Mouse Guard is a game of characters, and ultimately, if the events that take place within GM‘s turn do not connect to the characters then the game is unlikely to succeed.