My blog about my wargaming activities. I collect a lot of 15mm miniatures for the American War of Independence and so collect a lot of rules for this period. I started miniatures with Napoleonics, so I have a number of armies in 6mm and 15mm figures for skirmishing. I have15mm WW II figures that I use for Flames of War, Memoir '44, and someday, Poor Bloody Infantry. Finally there is my on-again, off-again relationship with paper soldiers that I sometimes write about.

Friday, November 18, 2016

Converting Rules to a Grid and a Small Gaming Space

I don't know about you, but I am getting old. Miniature wargaming is beginning to take its toll on me. After a gaming session I will usually have back and leg pain – not really bad pain, but annoying pain. I think that is why for some time I have been drifting to board games with miniatures. You still get some of the visual appeal of miniatures, and you get the small, easily reached boards. However, sometimes you want to try some miniatures rules that are not designed for a grid, or maybe even for a small gaming space. Now I am lucky to have a whole guest house as a gaming space where I can leave things set up, but even so, I don't always want to use that much space. Maybe I have a big game set up that is playing out over time and I just want a small, quick game and don't want to disturb the big game. Or maybe my back just hurts and I just want to play a game at a small table where I can reach everything.

So, when I tested out Neil Thomas' rules Wargaming Nineteenth Century Europe 1815–1878 (WNCE) I needed to use smaller units so I would, frankly, not have to have so many bases. I could get started quicker. When someone asked on a forum how to convert another set of rules to a grid I thought I would elaborate on my response to him in this article.

It is all about ratios

If you want to keep the flavor of a game intact – the way that the rule's author intended – you really need to understand that there are a few ratios that are critical. One if the ratio of a unit's frontage to the distance it can shoot. So many rules with flexible basing requirements fail to mention this. If you halve a unit's frontage, but keep the shooting range and angle of fire the same, you have doubled the firepower density of the game. You will find that it plays much bloodier and therefore faster. Other rules in the game might be thrown off by this. An example would be that if you get 'X' number of hits in a turn you have to take a special morale check. If achieving 'X' hits is considered exceptional, doubling the firepower will make this more common and thus you would be taking more checks than would be considered normal within the course of a single game.

Unit Frontage

I was not only converting WNCE to a grid, but I was changing from a four base unit to a single base unit, so I really needed to look at the unit as a whole. I needed to look at the unit frontage for the base rules and compare it to what I was going to use. Neil's recommendations for basing 15mm figures is 40mm wide bases with four bases to the unit. However, units are arranged in formations of two ranks of two bases each. (There are some exceptions to this, of course, which I will cover later.)

Given that three inches is 76.2 millimeters, the two formations are roughly the same size in width and depth. (Why 3" bases? It all began when I was ordering from Litko and instead of selecting 50 bases I selected 500... I was wondering why they were so expensive!) Rather than do complex math I decided to call it even; one of my bases if the equivalent footprint of a 15mm infantry unit in Line formation (or a cavalry unit) in the base rules.

Base Widths and Unit Widths

The first time I encountered rules using "base widths"(BW) as a unit of measurement was the Polemos rules system. (They also have "base depths", or BD measurements which are essentially 1/2 a BW.) DBA 3 famously went to BW measurements and upset more than a few people. So what is BW measurement? Quite simply it is changing all of the measurements in the rules from a set number of centimeters and inches to increments of whatever the width of your bases are. In this case, because I am using the distance of a unit's frontage, it would more properly be called Unit Widths (UW).

By converting all measurements to UW, we can maintain the ratios of unit frontage to shooting distance and movement distance. Here is what the converted movement distances would be, in UWs.

Unit Terrain Deduction per Turn
Open Woods or Town Crossing Streams Road
Infantry (Loose Order) 1 1/2 1 1 2 1/2
Infantry (Close Order) 1 1/2 1/2 2 1/2
Skirmishers 1 1/2 1 1/2 1 1/2 2 0
Cavalry and Dragoons 2 May not enter 1 1/2 3 0
Artillery 1 1/2 May not enter May not cross 2 0

Just a note about the Deduction per Turn column. In Neil's base rules the number represented a fraction of the movement that the unit lost for each turn. (Turns while using Road movement were never penalized.) The numbers here represent UWs, not fractions. Because I am using 1/2 UW as the minimum unit of measure (more on that later), I have rounded the values up, which makes units less maneuverable than in the base rules. Not an ideal solution, but as you will see, with a grid turning becomes less of an issue.

The shooting ranges are also easily converted to UWs.

Weapon Range
Steel Rifled Artillery 7 1/2
Bronze Rifled Artillery 6
Smoothbore Artillery (Shot and Shell) 4
Smoothbore Artillery (Canister) 1 1/2
Later Breechloading Rifle 3
Early Breechloading Rifle, Rifle Musket 2
Smoothbore Musket 1
Skirmishers +1 to Rifle or Musket Range

You immediately start to see an issue, however. There are a number of 1/2 measurements. The original goal in my mind had been to make the game board's grid size the same as the UW. In my case that would have meant 3" grid squares.

My intent was not to allow bases to position themselves diagonally within the grid, but only orthogonally. So a square grid that was 1 UW by 1 UW would allow you to fit two units in a square and you would know which unit was in front of which, and which way it was facing. Units would have to be aligned horizontally or vertically, but units could face in opposite directions. But if I allowed for measurements of 1/2 UW/grid, it would be a little more awkward.

So the best decision was to make each grid 1/2 UW and to double all of the measurements. This would still make the ratios between unit frontage, shooting range, and movement distance correct, but would make counting and positioning easier.

So now our data tables look like the following.

Unit Terrain Deduction per Turn
Open Woods or Town Crossing Streams Road
Infantry (Loose Order) 3 2 2 4 1
Infantry (Close Order) 2 1 1 4 1
Skirmishers 3 3 3 4 0
Cavalry and Dragoons 4 May not enter 3 6 0
Artillery 3 May not enter May not cross 4 0

Weapon Range
Steel Rifled Artillery 15
Bronze Rifled Artillery 12
Smoothbore Artillery (Shot and Shell) 8
Smoothbore Artillery (Canister) 3
Later Breechloading Rifle 6
Early Breechloading Rifle, Rifle Musket 4
Smoothbore Musket 2
Skirmishers +2 to Rifle or Musket Range

There is only one more measurement in the rules and that is the retreat move, which comes out to 3 grids.


The one area where most people complain about grids – especially square grids – is shooting or moving at odd angles. Actually, these odd angles are generally what create the most friction (read: arguments) in games. Is the enemy within the 45º firing arc, or are you turning greater than 90º, when the movement penalty is doubled, and so on. Further moving at angles other than orthogonally means you inevitably run into a scenario where you are a fraction of an inch or a centimeter in or out and time is spent debating whether the shot or the charge should be allowed or not. (It happened at my last game of Black Powder and was settled with a die roll as the two players could not agree. Still, this does not happen in grid games.
That said, if you do not want players be forced to fire or move straight forward, you need to devise a method of counting distance. I always liked the way Rivet Wars counted distance.
When calculating the range to the target, only a single diagonal may be used.
These are examples of what that rule means.

The red path shows that it counts three squares, one diagonal and two verticals. The green path shows one diagonal, three horizontals, and one vertical. The one vertical is because the rule specifically only allows one diagonal to be used when counting distances. Note that Rivet Wars tends to have must shorter distances, so it works. In WNCE you can see that the measurements are as short as 1 (the movement of Close Order Infantry in Woods) to 15 (the range of Steel Rifled Artillery), so perhaps it is better to allow one diagonal per 8 grids in distance.

Note that this would apply to all distance counts, such as movement. If a unit can move 3 grids, this move is perfectly legal.


All turning is by 90º, which is one way to justify the high penalty. A unit turns by changing its front face by 90º or 180º. Turning 180º is easy; simply reverse the facing of the unit, keeping the unit in the same two squares as they started in.

Turning 90º can be handled in two ways, depending upon how maneuverable you want your infantry units to be. (Remember, only Infantry takes a deduction for turning.) In the figure below, the light blue rectangle represents the starting position of the unit, before the turn, while the medium blue rectangle represents the ending position. The arrows represent which way the unit is facing.

If you want units to be fairly maneuverable you could allow all four maneuvers, which essentially represents wheeling the unit left and right, forward and back. If you think they should only be allowed to wheel forward, then only allow options 2 and 3.


There are three exceptions in my conversions: Skirmishers, Artillery and Infantry Columns.

In the base WNCE rules the Skirmisher unit is only two bases. We can easily handle that by allowing 1/2 the hits before the unit is destroyed. The primary difference comes in that the formation is always one rank of two bases, so when reducing this down to a single base, the unit footprint should actually be 1/2 the depth of the Infantry and Cavalry formations, i.e. 0.75" for me. In the end, I don't think that really matters. Further, in WNCE Neil never specifies the depth of any stands, so I don't think it really entered into his equations either.

Artillery is even smaller in that in the base WNCE rules the Artillery unit is only one base. That means that the unit in these rules should also be 1/2 the width and 1/2 the depth. I did not do that but instead used a base that was 1 1/2" wide and 3" deep. *Cough* The 1 1/2" width makes the Artillery unit the proper width and the 3" depth allows me to put a limber behind the artillery, facing away. That way when the Artillery is limbered and on the move the horses face forward, while when deployed the gun faces forward. It looks much better and saves me from sawing bases in half. So again, a compromise in that I used a base twice the depth expected. (Artillery bases are traditionally square and not rectangles, as the models are so deep.)

Finally we get to Infantry in Column formation. One of the main points of going to a single base per unit – besides the obvious point that it would take me less time to get up and running – is that I don't need to account for formations anymore, or at least not in the traditional of shuffling figures around. In WNCE you change formation only with Infantry (Skirmishers and Cavalry only have one formation and Artillery is either Limbered or Deployed). You change to Column when you wish to move and you change to Line when you wish to fire more effectively. There are a couple of exceptional armies – the British in the Crimean War get to move in Line and the Austrians in 1864 and 1866 always stay in Column, as do the Russians in the Crimean War – but for the most part you can simply indicate the formation by indicating the movement. However, even Neil gives an exception in his rules. If you are in Line and you turn, you are still in Line, but you fire as if you were in Column.  So that is an exception I also deal with. If a unit in Line wished to turn, but make no other movement, I mark it in a special way denoting that it is in Line (which matters for Hand-to-Hand combat), but fires as if in Column (which is much less effective). I deal with it by placing small arrow-shaped markers. If the arrow is green, the unit moved as a Column. If the arrow is brown, the unit turned while in Line. Simple.

When I did my test version of the WNCE rules, I was using these conversions, although I had not fully marked out the 1 1/2" grids (they were still 3", but I played on and counted the half grids). I think it worked pretty well.

Now that I am expanding my armies, I am looking to how to scale the grid game up as well. Actually, it is pretty easy. If you double the frontage of the units from one base to two, you double the grid values in the tables. (You will also be doubling your table size, but that is another issue.) If you finally get to the point where you have collected and painted four bases per unit, you are just doubling the depth, so there is no reason to adjust the grid size or counts any further. Four bases per unit plays the same as two bases per unit.


One final thought, and that is about marking hits on the bases. The WNCE rules use four hits per base removes the base for a total of 16 hits for Infantry and Cavalry, 8 hits for Skirmishers, and 4 hits for Artillery. I simply use one color marker to represent hits and another color to represent bases lost. As firing and hand-to-hand combat is affected by the number of bases you have in the unit, I simply count one less base for each marker representing a lost base. I never found it to be a problem at all, it just surprised me when I momentarily forgot that Artillery had one base and it disappeared quicker than expected.

Even Neil is Too Relaxed Sometimes

If you read the WNCE rules one thing you will notice: Neil has five recommended base sizes, indicated by the size of the figure being used. What Neil does not discuss is the need to adjust the movement and firing distances based on which basing scheme you choose. If you approached his rules from a purist viewpoint, the 2mm troops and the 42mm troops would share the same move and firing distances despite the latter having more than three times the unit frontage the former. The smaller the scale, the bloodier the games would be as more units could bring their firepower to bear on a single, enemy unit. It is only my assumption that the distances in his rules are actually associated with the 15mm scale. It could just as easily belong to the 28mm scale!

Well,  this is basically my approach to adding a grid to my games. I hope you found this instructive and useful, or at the very least helps you save your back from bending, stretching and reaching over those large tables.


  1. Interesting thoughts - and yes, grids massively help the old back! I rather feel though that by getting hung up on unit frontages rather than the grid itself and going to half base frontage, you have built some complications into your model that needs extra thinking and calculation.

    As an alternative, I make the grid scale the prime mechanic to gridding a game. So for example in Neil Thomas ACW rules in his 1 Hour Rule set, I decided that the lowest common denominator was 6". Everything (movement rates and weapon ranges) could be divided down to 6". So with that done, a grid equalled 6 inches. His battlefields are 3' x 3', so my grid would be a grid 6 x 6.

    As an aside he says that a unit should have a frontage of between 4" and 6" and so coincidently that fits the grid, not that it matters. the rule then becomes that a grid is allowed to hold 1 unit. Once you go to grids, what the base actually looks like doesn't actually matter, because it is the grid that matters and not the base, so each base could actually be a rather splendid pair of 54mm's or 100 6mm's in several ranks.

    My conversion did have 1minor problem, his elite foot could move 9" and that obviously cannot be represented with ease on our 6" grid ..... easy, I couldn't find any justification to give elites a 50% advantage in movement, so instead I returned them to a 6" move, however, I did introduce morale rules (after fire) into the game and that returned an advantage to elites, so that during play they did perform better ... just a different type of performance..

    If you don't mind, I am including a link here of a blog entry of how I hexed one of his games (Please delete this response if you are not happy with that) LINK -

    I have an interest in grids and am sensing that there is an increasing 'tolerance' of them theses days. In fact the gent who has the ancient set 'To the Strongest' seems to have been able to commercially offer his rules.

    Again, I enjoyed the post, interesting to see a fellow back sufferer come to the same conclusion.

  2. Very enjoyable and informative posts, both the original and the comments by Norm. I too have a liking for small table gaming, I have not tried a grid system but I can see its potential. I am currently starting out on an ACW campaign game using the rules and scenarios from OHW. I simply changed inches to mm, and am actually playing on a cushion that is approx 40 x 40 cm, it seems to be working so far.

    1. I've read those posts. Good job.

  3. Terrific topic and excellent analysis, Dale! I need to read more carefully before I weigh in further but grids do speed up play.

  4. Excellent crystallization of shrinking and gridding games. As you may be aware, I have been fond of small scale battles and shrinking rulesets designed for larger spaces into smaller ones :-) So having your post is great as it nicely documents the shrinking issues. Gridding is something I toy with but other than the boardgame-miniatures crossovers such as WarHammerQuest and Zombicide, I have not managed to really embrace grids. However I do have an ongoing side project to produce a portable miniatures WW2 game that is definitely going to be based on grids (it has it origins in the CCS Tank Commander). I think I have produced about 6 very different drafts of the potential rules over the last 12 years, all of them crap!

  5. Thanks Dale, I have not switched to grids yet, but I am a small (4x3') table guy, and rules conversions are always something I am toying with. Good Insights thank you.


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Huachuca City, Arizona, United States
I am 50 yrs old now. I bought a house in Huachuca City, AZ (although I have a townhouse in Houston, TX and a small home in Tucson, AZ) working on a contract for "the next two years" that is going on five years now. To while away the hours I like to wargame -- with wooden, lead, and sometimes paper miniatures -- usually solo. Although I am a 'rules junkie', I almost always use rules of my own (I like to build upon others' ideas, but it seems like there is always something "missing" or "wrong").