I like the DBA (De Bellis Antiquitatis) game rules a lot. Their simplicity and speed offer great appeal in the ancient-medieval periods and the rules seem quite adaptable to other periods as well. In addition, I subscribe to the authors' view that the "system is more subtle than may be immediately apparent."

But there is one thing about DBA that I have been tinicering with and that is the army lists found at the back of the book. I have no problem with the historical accuracy of the lists. I'm willing to go along with that, especially because all armies in those lists must be simplified to a mere dozen units. There's not a lot of room for variation there.

Yet that is exactly my problem. When I field a DBA army, I'd prefer that there be more opportunity for some uncertainty as to what forces may be arrayed, both across the table and in the army I happen to be commanding that particular day. Real armies were changeable things, with units joining and being detached as time went by. Even on campaign, a commander couldn't count on fielding exactly the same units in two separate battles.

So, randomizing orders of battle has been my latest project. I've tried different approaches, but here's the basic idea:

• Create a pool of available forces from which to choose your units.
• Break down the individual types of units or elements into percentages of the force pool.
• Use cards or percentage dice to randomly choose your 12 elements for a DBA army.

Creating a Pool of Available Forces

There are many ways to go about setting up your force pool. Perhaps you aren't bothered much by "official" lists and simply want to use the troops you have available. In that case, your force pool is just that, the troops you have painted up, ready for battle, for your particular army. Here, your work is easy. Just list your troops by numbers of elements and types.

As an example, let's say you have a Marian Roman army on your wargaming shelf. What you have consists of 20 elements of Blades (Roman legionaries) 6 of auxiliary cavalry, 4 of psiloi. That's your force pool for your Marian Roman army.

Or maybe you are partial to someone else's list. The De Bellis Multitudinis lists, put out by the same folks who brought you DBA, offer quite detailed breakdowns of many ancient and medieval armies. If you want to use one of those to create your force pool, just jot down the maximum number of elements for each type of unit that is listed. In this case, you will have to simplify certain troop gradations.

O and S Spears, for example, probably will both become simply, Spears. In addition, you probably will be eliminating certain other elements, such as boats, ships and fortifications. In other words, you will do some customizing of these lists to reduce them to a usable force pool for a DBA army. Sticking with the Marian Romans, a force pool based on their DBM list could include 48 elements of Blades, 6 of Cavalry, 6 of Light Horse, 26 assorted Psiloi, 16 Auxiliaries and 6 elements of bolt-shooter artillery. (I've left out allies as well, to keep this example uncluttered.) And, don't worry, you won't need anywhere near all those elements for the table. These numbers are merely those that are hypothetically available -- on paper, in other words.

Armati is another rules set that provides useful army lists for the periods covered by DBA. The Armati lists are less involved than DBM's, but Armati armies convert easily to DBA troop types. The force pool for an Armati Marian Roman army would include 8 elements of Blades, 1 of Auxiliaries, 3 of Psiloi and 2 of cavalry.

Setting up Percentages for Each Type

Once you have your basic numbers of elements for each troop type, add all those numbers to get a total for the entire army. In the first example above, your total would be 30 elements; 108 elements in the DBM example; 14 in the Armati example.

A quick bit of math will give you the percentages of each troop type as related to the whole. (For us nonmath types, a calculator is handy here.) Just divide the number of each particular type of element by the total number of elements in the army. If there are, say, 20 Blade elements out of a total 30 army elements, divide 20 by 30, giving you 67 percent. So, your Blades are 67 percent of your total available force. Do that math for each troop type represented in your army.

Once again using the original "off the shelf" example, your Marian Romans could break down into 67 percent Blades (20 elements), 20 percent Cavalry and 13 percent Psiloi.

At this point, for more simplicity's sake, I adjust all the percentages to even numbers. You'll see why in a moment. So, let's convert the example to 66 percent Blades, 20 percent Cavalry and 14 percent Psiloi.

Randomly Choosing Elements

I now divide each percentage by two, getting (again from the example) 33 Blades, 10 Cavalry and 7 Psiloi. The numbers now add up to 50 and here's where I take a deck of playing cards, discarding two of them (a pair of Aces or Kings is convenient). Assign each remaining card an element type, shuffle thoroughly and deal out 12 cards. Those 12 will give you a DBA army breakdown. Statistically, you will generally have an army similar to the proportions you originally started out with. But fluctuations are possible.

Even with Marian Romans, you could end up with lots of Psiloi and Cavalry and relatively fewer Blades than the standard army list you started from. There's enough of a range to introduce some uncertainty into what type of force you (or the army across the table) actually will put on the field that day.

Alternately, you can use percentage dice to run through the final step of the process. But drawing cards assures that each value will only turn up once, while percentage dice leaves open the possibility of repeating a value. In other words, the Six of Spades, once dealt, won't be dealt a second time, while a roll of 54 on the dice could in theory come up repeatedly, affecting the selection from the pool.

Like lots of game rules, this all sounds a lot more complicated than it really is. Setting up and choosing random force pools has re-invigorated my DBA soloing. Now, I want to perfect that system of random terrain selection I saw on the Internet....