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Sunday, 21 January 2018

Cards and Cannon

To resolve cannon fire (or other types of fire), most wargaming rules use a ruler to measure distance, followed by a die roll to determine casualties. Many variations are possible, but the basic structure of measuring the range to the target and rolling for damage is a constant in dozens of wargames rulesets.

However, other approaches are possible as well.  It is well-known that H.G.Wells used toy cannon, shooting matchsticks. Although most wargamers do not like the idea of damaging their figures this way, there is something to say for more tactile mechanisms such as the one used by Wells.

This article describes a procedure for resolving cannon fire, by using cards to lay out the firing path.

A Path of Cards

I encountered this mechanic in Miniature Wargames issue 264, April 2005 (I often look up old articles, and then happen to come across something more interesting ;-)), in an article titled "A Deck of Cards", written by Andy Philippson. The article describes playing mechanics using ordinary playing cards. It is mostly about drawing cards to activate units, but one particular mechanic about shooting cannon drew my attention.

In order to determine whether a cannon hits its target, take the cards 2-10 from one suit, plus the Joker (10 cards total). Now, shuffle the cards, and lay out the cards in a straight line lengthwise, starting from the gun towards the target:
  • If the card that reaches the target has an even number, the target is hit. If the card is odd, the target is not hit.
  • If the Joker shows up before the row of cards have reached the target, this means the shell has "exploded" prematurely, and the shot stops right there (and yes, I know that a cannonball does not really explode in mid-air :-) , but as with many mechanics, invent your own favourite explanation for this effect ...).
  • If the Joker shows up as the first card, the cannon explodes and the crew takes damage.
  • If the "2" or "10" shows up, this means the shot deviates, and you place the next card 1 card-width to the left (if the 2 is first encountered), or to the right (if the 10 is first encountered).
That's the idea. Of course, you still need to fill out some more details regarding damage etc.

I quickly set up some ACW figures to show the mechanic in action (images taken with an iPad, they could have been of better quality ...):

The path of fire is laid out, with the "2" indicating a deviation to the right. Since the last card hitting the target is odd, the shot does zero damage.
The Joker shows up, ending the shot. No damage to the target.
The "10" deviates the shot to the right, with the "2" a further deviation. The shot passes next to the target.

The use of the Joker stopping the shot might seem a bit harsh, but actually makes this mechanic a fine-grained distance modifier. We have 10 cards, so the joker could turn up with 10% probability in any of the card positions along the firing line. You could see this as a variable range (the shot can be 1 card length long, 2 card lengths long, ... each with 10% probability of occurring), but as we have shown in a previous post, random ranges are (sometimes) equivalent to distance modifiers. So, this mechanic has a more fine-grained distance modifier compared to a single die modifier for "over half range", as is often seen in rulesets.

It might seem a bit strange not to measure the distance between the gun and the target. But actually, we do. We measure the distance in units of card length instead of inches or centimeters. That's a perfect valid measure, although perhaps a coarse one. But that doesn't really matter, since the measured distance is usually only compared to the maximum or half range of the gun. If the maximum range is, let's say 24", it isn't that important whether you measure that distance in inches, centimeters, or card lengths.

The additional feature of deviation is another (geometric) probability built in to determine whether damage is inflicted or not.

Thus, this mechanic is perfectly capable of capturing the results of a more traditional ruler-and-dice approach. It comes down to whether you like this particular mechanic better. Laying out cards like this creates a unique tension ... when you turn over the next card in the sequence, there's always the possibility that the Joker turns up and that your shot will fall short. As the sequence of cards is laid down, you know the Joker can stop your shot with increasing probability ... this suspense during the resolution is more difficult to replicate with a simple die roll.

Moreover, laying out the cards creates a nice visual mechanic, comparable to using a cone-shaped firing template. Fantasy wargaming uses this mechanic fairly often for all sorts of (magical) effects; in historical wargaming it is considered somewhat old-school, but firing templates are often described in the books by Featherstone or Grant.


The mechanic as described above uses 10 cards (including the Joker), but you could easily increase or decrease the number of cards for making the effective firing range longer or shorter. Perhaps the number of cards could depend on weapon type, or other tactical modifiers.

The number on the card that hits the target (odd or even) determines whether damage is inflicted or not. But you could also use the number itself as an indicator of damage inflicted. That would open a new set of possibilities with damage ranging from 2-10, or any other range depending on the selection of cards. Obviously, this needs to be tuned with the rules in use.

Just as the "2" and "10" indicate deviations, you could add more cards that do exactly that, or less cards ... again variations can be introduced, perhaps even by printing out custom cards specifically tuned to various weapon types.


When reading the article, I remembered I had seen this mechanic before. And suddenly I remembered! The classic Games Workshop/MB game Battlemasters (1992), still fondly remembered by GW afficionados of the late eighties/early nineties.

Battlemasters is played on a hexgrid, and also includes a cannon for the Imperial army. When the cannon shoots, a path of cards is laid out, hex by hex, till the cards reach the target. Again, an explosion stops the shot early, and there is the same rule that if the explosion is the first card, the cannon takes damage. There is no deviation left or right, but there are cards that make the ball "bounce", inflicting reduced damage if any troops would be present in that location.

I still have the components of Battlemasters lying around (the figures have long been drafted for other uses), so here they are, illustrating the principle in action.

My original Battlemasters cannon, aiming at some Treemen. Put the target card at the Treemen's hex.
The path of the projectile is laid out using cards. Sometimes the ball bounces, sometimes the shot falls short.
When the shot reaches the target, turn over the aiming card, and damage is done!
The similarities between Battlemasters and the mechanics described in the Miniatures Wargames article are very obvious, even more so because the article has activation mechanics almost identical to Battlemasters. Thus, I assume that the author has drawn his inspiration from Battlemasters - 13 years later - to develop his own card-driven wargame.


I think this mechanic is a nice visual representation of a cannon shot, especially if you would use custom-printed cards to add to the drama. The card deck can be tuned such that in terms of to-hit probablity and amount of damage, the same effects can achieved as with a more traditional ruler-and-dice mechanic.

I wonder if any other rulesets have used something similar? Let me know!

  • Discussion on The Wargames Website.
  • An interesting suggestion was made on TWW: you could use a suit of cards, or even a full deck, but define the effectiveness of a gun in terms of which cards would "stop the shot", just as the Joker does. So, you could have a "Queen-gun", meaning that whenever a Q, K or Joker shows up, the shot fails. Similarly, you could have a "10-gun" etc. Maximum firing ranges would not be necessary, since the shot will statistically fail sooner or later depending on its type.


  1. Thanks Phil, an entertaining mechanic, but not one that I would care to see in any of the games that I play.

    The only thing I can think off that added something to the standard fire process for artillery was good old ‘bounce sticks’

    1. Norm,

      Yes, firing templates, bounce sticks, ... I consider them all mechanics to make the firing more "visual". The thing I wanted to point out is that although such mechanics might seem somewhat "less serious", you can actually obtain the same statistical distribution of results compared to a ruler-and-dice mechanic.

      But I fully agree that in the end, it's all about what you like best in your own games ...

  2. Thanks Phil, interesting ideas and read.


  3. This is a brilliant mechanic! I'm thinking of trying it out for my WW1-themed game for artillery strikes. It's got a very interested "push-your-luck" element that I think would really add tension. I'm also looking forward to trying out a creeping barrage using this mechanism! Thanks for the post!

    My only concern is if there are other miniatures in the firing path that the shell would fly over. I would have to either place tokens/cards around the units, or somehow represent the firing path off of the board.

    1. Sorry, I missed your comment for moderation ... Hence the delay in getting it published.

      Anyway, the mechanic for Battle Masters also had some "bouncing cannon ball" cards. If you would fir over an intermediate unit (depending on rules for LOS etc), and the bouncing ball turned up in the hex exactly where an intermediate unit was, that unit would also get some damage, but the cannon ball would keep on following its trajectory.