Game design musing: “Sims” (with a sample sports sim for GURPS)

In this post, I muse that it’d be interesting to see examples of ways to game a sporting match in GURPS (or whatever game you like). By which I don’t mean some per-second simulation of every dash and tackle and kick by every player on the pitch, a la RPG combat. (Lordy, just imagine trying to play out a combat turn-based simulation of two 40-minute game halves. “Okay! We begin with Turn 1 of 4,800!”) No, I refer to some abstract simulation that resolves a complex activity in far less detail than what RPGs typically lavish on combat systems, while offering more of interest than a simple “Roll vs your Sports skill. Success wins the match.”

Actually, “sporting match” here is nothing more than an example; what I’m really talking about is lightly-detailed simulations for just about anything. My interest here goes back to my D&D days, when I needed something to appease a player who wanted to send his PC off on pickpocketing sprees at the market while the other PCs did their things in town. I came up with some (now long lost) table that let a few different abilities come into play, with built-in chances for rewards and mishaps both large and small. It worked well enough for an off-the-cuff toy, and the player was happy. I later came up with other occasional “sub-systems” for resolving travel times or hunting success or other results of extended endeavors that called for a bit of detail (but not too much).

Just for fun, I’d like to introduce such an abstract simulation below, for a fantasy sports match. But not without some dull blathering first.

Meet the Sims

I’ve long informally referred to such simulations as “sims”, for lack of a better name (or even trying to think of one). These are little abstract sub-systems that fall between the simplicity of “Roll vs X” and the full-blown detail of combat systems, playing out some extended task as a “mini-game” with a handful of rolls and just a few minutes of table time.

RPGs offer such sims in spades, of course. Looking to GURPS for examples, it’s clear that the game handles a lot of situations with single rolls—as appropriate for picking a lock, calming an animal, spotting a clue, or other straightforward tasks focused on some single ability. But there are some systems that fall under what I’d call a sim. The Basic Set‘s rules for invention and gadgeteering can bring multiple skills and other inputs into the workings. Action 2: Exploits offers a simple sim for disarming weapons of mass destruction, in which failed rolls for certain ancillary skills penalize the actual disarming skill roll (by abstractly representing lost time). The same book also provides a fine sim for abstractly gaming chase scenes, with numerous factors and abilities coming into play.

GURPS‘ job roll, a fun feature for handling non-adventuring income, is a sim of sorts, requiring a job-holder to hold some number of prerequisite skills or other traits, then roll against some target (typically a given skill) to determine success for the month. Normal success or failure typically affects income only if the job is freelance or otherwise not “steady”. But income can also vary with the prerequisites, and critical rolls have interesting effects for any job.

Room for improvement?

In short, there’s a lot out there, and most of it is simple, fast-playing, good stuff. I particularly like any sim that calls upon multiple factors that could affect the outcome (or, where possible, multiple interesting outcomes). That’s where some sims could perhaps be buffed up. Take those job rolls. A job may list skills A, B, and C as prerequisites, but if the success roll or income is based on only one of these (a specified skill, the highest skill, or the lowest skill, as noted for the job), then only that one really matters; the other skills don’t figure into results, whether their level is 12 or 20. It’s certainly no big problem, but it can feel a bit static.

But how can you best make multiple inputs matter, especially when their number is large? Just imagine how many abilities would realistically factor into, say, a police officer’s day-to-day work. Administration (Police) and Law (Police) are givens. Then there’s Streetwise and Criminology for working cases, Observation for stakeouts and spotting clues or trouble, Driving and Running and Guns and Wrestling and more for moments of action, plus Current Events and Streetwise and Area Knowledge and any number of social skills and even plain attribute rolls and . . .

Working out a final result from rolls against all of those would be ridiculous. Converting all of those inputs into some big static modifier or an “averaged skill” would let them all have a say in one all-encompassing job roll, but prepping the numbers for that roll sounds dull.

To work multiple inputs into a sim without tons of rolls or boring calculations of complex mods, the best I can suggest is this: Use whatever inputs are clearly required (like Singing skill for a job roll as a singer), plus one or more inputs randomly selected from an interestingly long list of inputs. The result: the character in question won’t be tested on all of those potential inputs, but there’s no telling which of them fate might call upon. So it’s best to be prepared for as many as possible!


Enough with the ocean of exposition; sorry to keep you waiting (wading?). Here’s my crude example: a GURPS sim for the dwarven sport of hammerball. (Think field hockey, with hammers, shields, and stumpy legs.) Follow these three steps to settle a match:

1. Roll PCs’ performance mods

The match will be decided by each team trying to roll higher on 3d—a roll that athlete PCs can affect.

For each PC (on either team), make the following three rolls as complementary rolls, i.e., record a +2 for a critical success, +1 for a normal success, -1 for a failure, and -2 for a critical failure. Total the PC’s three results to get that PC’s “performance mod” (which will range from -6 for three critical failures to +6 for three critical successes).

1. Test of skill: Roll vs the game’s core skill of DX-based Sports (Hammerball).

2. Test of chance: Randomly select a test below by rolling 1d, and make the indicated ability roll for the PC:

  • 1: Take a shot! (Axe/Mace)
  • 2: Block a shot! (Shield)
  • 3: Spot an opening! (Per-based Sports (Hammerball))
  • 4: Make a power shot! (Striking ST (same as ST for most characters))
  • 5: Tough it out! (HT + DR (including Tough Skin) ±3 for High/Low Pain Threshold)
  • 6: Brutal scrum! (Highest of Brawling, Sumo Wrestling, and DX)

3. Test of glory: Roll vs a different one of the above 6 items, chosen by the player.

2. Set NPCs’ performance mods

Don’t bother statting up NPC athletes and rolling their performance mods (unless you really want to!). Rather, hand NPC athletes a performance mod ranging from -3 for an amateur to +3 for an all-star, with +1 as the norm for a respectable athlete. For simplicity, feel free to use the same performance mod for all NPCs on each team, as an averaged value.

How many NPCs does each team have? It’s up to you, but I have it on good authority that the MHL (Moria Hammerball League) regulates 5-player teams. That means a team can have between 0 to 5 PCs, with NPCs making up the remainder of each team’s 5 athletes.

3. Roll each team’s overall performance as 3d + its athletes’ performance mods

For each team, roll 3d + the sum of its athletes’ mods. The team with the higher result wins!

Example: In today’s MHL hammerball match, The Forty-Miners are fielding one PC. The player makes her three rolls. Her test of skill yields a critical success, for a +2 complementary bonus. The 1d roll for test of chance results in a roll vs Shield, which the player fails; that’s a -1. For the final test of glory, the player chooses another item: the PC’s super-high Brawling skill, which succeeds for a +1. The PC’s net performance mod is +2. The remaining four athletes are NPCs whose performance mods the GM sets to +1 each. The team ends up with total performance mods of +2 from the PC and +4 from the NPCs, or +6.

The opposing Khazad Khardinals are less favored: the GM assigns the team’s NPC athletes performance mods of +0 each. But today’s match features three PCs! The PCs’ players all make their three rolls as above (details omitted here); in the end, the PCs net a +1, a -2, and a +4. The team ends up with total performance mods of +3 from its PCs and +0 from its remaining two NPCs, or +3.

This game favors the Forty-Miners – but luck will have its final say! The Forty-Miners roll an 8 and add their +6 to score a 14; the Khardinals roll a 12 and add their +3 to eke out a 15. The sportscasters will chalk this one up to luck (despite particularly great plays by that Khardinals PC who contributed a +4), but it’s a narrow win all the same for the Khards!

It’s a start

That’s it. To the extent that any “designer’s notes” are even called for here, I’ll point out that I made a roll against the Sports skill a requirement—and gave it even more prominence by having it show up again as a possible roll in the test of chance. (I also changed the skill base there, to sneak Per into the sim.) I injected some traits that can’t really be rolled against—DR, Tough Skin, and High/Low Pain Threshold—by making them mods to a roll. Finally, I added a “player’s choice” mechanism in the test of glory as a simple nod to the idea that athletes can and will play to their own strengths, not just respond to what the match throws at them.

The end product certainly isn’t terribly detailed. Any number of further inputs could go into it. (There’s no role for fleetness of foot, for example. Hm, perhaps the test of skill could be made “DX-based Sports (Hammerball) -3 + Move”?) The sim lacks any rolls to check for injury (“Uh-oh, it looks like Grimli is down with a pulled beard muscle!”), or an option for player strategy (such as a way to pursue greater success through riskier play).

This sim doesn’t attempt to “play out” a match at all, whether in halves or quarters or any other number of key “scenes”. In the end, it comes down to “each team makes a modified roll” to settle the whole match. But that said, it does test multiple PC abilities, which was my primary interest. (It even yields a by-product that the GM could spin into game play: each PC’s individual performance mod could act as a reaction mod among fans for the next day or few.)

Most importantly, the sim lets you hammer out a match involving several PCs, in just a few minutes.

Rolling on

Sorry for all the blather; the sample sim itself is trivial, but the larger topic is (maybe) of interest to some readers. Does the above example depict my ideal sort of sim? No, not really. It’s a sort of sim I’ve used before, but I offer it here only as a sneak peak at what I’m really interested in: a more generic format for such sims. That is, a standardized format that can describe mini-games for sports, hunting, job performance, or many other sims, each whipped up by a GM with the ease of filling in a blank wandering monster table.

I’m still puttering about with that ideal format, but hope to have something to show before long!

Header image: The rivals (Orkshire Football Club?). Image source and license.


  • Keith

    I like it. Many opportunities to mod it. First one that came to mind for me was an opposed roll. Say each test has a 1 in 6 chance of being opposed, roll a contest vs opposing player and winner gets +1 or + 2 for winning the contest by 5 or more.

    • tbone

      Opposed rolls could certainly be inserted. Though I’d want to avoid too many rolls (which is to say, I’d want to save rolls for meaningful things like bringing another skill into the mix).
      Restated: If a contest pitted a PC against another PC, that could be fun! If it were a PC against an NPC, though, it’s quicker to just have the PC roll, with the NPC’s opposition represented as a static penalty.
      (Which still means an opposed roll, just as you say. I’m just suggesting one roll instead of two if the opposition is an NPC.)

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