Sunday, 14 May 2017

Range bands or random ranges?

Many wargaming rulesets contain a so-called "to-hit table", listing various modifiers to be applied to a die roll when you want to shoot at a target.

Such modifiers often list things such as "shooter has moved" or "target in hard cover". Usually, there is also some modifier for taking into account the range to the target. Very often, a distinction is made between shooting at half range or full range, with the full range defined by weapon type.

But sometimes, rules go further than the half range / full range distinction, and introduce additional range bands. Shown below is such a table I encountered in a ruleset published in a commercial magazine not too long ago:

As you can see, 5 different range bands for each type of weapon are listed. What makes this table objectionable to me, is that the range bands are not multiples of a basic range - as would be the case when you use half range / full range (or 1/3 range, 2/3 range, full range). The bands are uniquely defined for each weapon type (compare British Rifle to Jezail .... ). This triggers the question whether such a mechanic is playable. After all, very few players will memorize this table, and thus, one needs to check this table for every single firing action. This specific ruleset subsequently applies a modifier based on the range band, the equivalent of a +1/+2/+3/+4 on the die roll.

It might make sense to have such a detailed mechanic, but it strongly depends on the type of game. A skirmish game with only a handful of figures per player mandates more detail per action for each figure. Roleplaying games takes this to the extreme, where each player typically controls a single figure, and hence a lot of detail is provided for each individual action.

But whenever I encounter such range tables in miniature wargaming rules, I wonder: "Is this really necessary?" If you want to have a fine granular range modifier for a firing action, perhaps there are better ways to achieve that goal rather than providing a detailed table that results in an unplayable game. Such tables seem to add a complex mechanic just for the sake of adding a complex mechanic ...Whether such complex tables do have any resemblance to historical data - a possible rationale for justifying them - is also very questionable.

Continuous range modifiers

Let's look at the overall idea: the further away a target is, the harder it should be to hit the target, and we want to use something more fine-grained than simply half range / full range, but not resort to a complex table such as the one shown above.

A couple of years ago, I started a skirmish science fiction campaign (see posts labeled Antares on my other wargaming blog), and was looking for a mechanic to resolve firing. Whenever I write my own rules, I try to focus them around one or two mechanics that form the core of the system. For these rules, we use a hexgrid (we use Kallistra hexes), which makes it very easy to count any distance in hexes. When a figure wishes to shoot his personal fire-arm, he has to match or exceed the distance in hexes on a die roll. E.g. if the target is 5 hexes away, you need a 5+. If the target is only 3 hexes away, a 3+ is needed. The type of die is determined by weapon type. Some weapons use a D6, others a D8 or a D10 or even a D4.

The result is that we have a distance modifier at the granularity of the hex-grid, and the probability of hitting something goes down linearly in function of distance. Each additional hex implies the equivalent of -1 on your shooting roll. Players now have an incentive to get as close as possible to the target as is tactically sound to maximize their chance of hitting something. Since a distance of  1 hex implies a 100% hit probability, we usually designate a roll of a "natural 1" as a miss, a weapon malfunction.

This is not an original mechanic. I have seen it used in different variations in various rulesets that use a gridded playing surface, but it is a nice way to do away with all sorts of range-dependent charts. The only thing you have to remember is what die to roll. There might still be some modifiers. E.g. a target in cover counts as being at "1 or 2 additional hexes". The equivalent of this is a -1 or -2 die modifier. And instead of using only a single die (thereby implying a linear decrease in hitting probability), you could also use something like a 2D6 or 2D4, resulting in a very high probability of hitting something close-by, and a very low probability of hitting something that is far away.

The obvious drawback is that your die rolling procedure is tied to the distance in hexes and is tied to the granularity of the hexgrid. But then, that is also the case if you express distances in inches or centimeters. And often, range bands are expressed in multiples of 3 or 4 inches anyway.

Random hit vs Random distance

Let's look at our die roll >= distance mechanic from a different viewpoint:
Suppose I roll a D8 to fire. The maximum range at which I could hit something is therefore 8 hexes, and the probability of hitting a target at a specific distance varies with that distance.

But, I could also look at this differently. Let's say we will always hit the target, but we are not sure yet what the maximum range for our weapon is this turn, and this maximum range is determined by rolling a D8. So, we do not think as the die roll trying to beat the probability to hit within the maximum range of 8 hexes, but as the die roll giving the variable maximal range within which we will certainly hit the target.

Let's clarify with an example. Suppose a target is at 6 hexes. The first interpretation says I need a 6+ to hit that specific target. The 2nd interpretation says I need to roll the die first to determine distance (might be a 6 or more), and I will certainly hit within that given distance.

The difference is subtle, and one might say it doesn't matter. And that's correct. Mathematically, it doesn't matter for this specific mechanic. But it does allow us to make  the mental jump to a different firing mechanism, in which we do not think about our  firing mechanic by setting a probability to hit something, but rather to set the distance within which we will hit something with 100% accuracy.

How to make random distances work?

Let's therefore propose a new firing procedure. When you shoot, you will hit with a 100% accuracy, but we will randomize the maximum firing distance for the shot. So, we have traded variability of hitting something within a fixed distance for the certainty of hitting something within a variable distance.

How can we make this work as a procedure within a wargame? Let's list some possibilities:
  1. The obvious solution could be to roll dice for distance, just as we explained above. Rolling a single D8 or D10 gives you a uniform distribution of distances, but as hinted at before, you could easily modify this by altering the combination of dice to roll. Rolling 2D6 results in average distance of 7 hexes, 7 inches, 7 whatevers, ... with the probability being very low for reaching out a full 12 hexes. Of course, these numbers have to make sense within the framework of other distance-dependent rules, but this is equally valid for a more traditional firing procedure. Other alternatives could be to add fixed offsets, such as rolling D6+5 etc.
  2. Since we need a randomizer to specify a distance, any type of randomzier can do. A pack of cards, giving results between 1 and 13, can serve as well. The suit of the card could signify secondary effects, such as friendly fire, a misfire, an exceptional lucky shot, etc. Alternatively, custom cards with desired distributions of ranges can be used. Or replace the cards with chits, to be drawn from an opaque cup ...
  3. More tactile gaming mechanism can be considered as well. One idea I have never tried myself (but sounds wildly attractive) could be to use a set of skewers and paint them in different range bands, each at slightly different lengths on each skewer. By randomly drawing skewers, one has an immediate randomized measuring stick indicating the true extent of the range for a specific shot.
  4. Guessing distances might be another mechanic. I know many wargamers are hostile towards such an idea, but it has a strong pedigree in wargaming (e.g. the famous Fletcher Pratt naval wargaming rules during the 1940s). Guess the distance, and if you're within a certain threshold, it's a hit, otherwise there could be some lessened effect if within a secondary threshold etc.

What I wanted to show with this post is that overly complex range bands are probably not a good idea to use as a procedure in miniature wargaming. Rather, use a different mechanic if you want to use a fine distance granularity for your firing. And secondly, when putting your mechanic in a different perspective, you could end up with doing something totally different, like drawing skewers.

But, as I have emphasized before - a mechanic is not a goal in itself. It is always embedded in a larger set of rules, and any given mechanic has to make sense within that larger framework. But it doesn't hurt to think about some alternatives now and then ...