Airborne landings

Airborne operations are often associated with elite troops, carrying out daring missions. Eben-Emael, Crete, the D-Day landings, Arnhem, ... all of them have become the stuff of legend.

A wargame scenario involving an airborne landing always poses some interesting challenges mechanics-wise. One of the aspects of an airborne deployment is the unpredictability of where the troops will land, and I think it deserves attention in a wargame as well.

Air Assault on Crete

The first game I played (back in the 80s) that involved airborne landings was Avalon Hill's Air Assault on Crete. This is a classic hex-and-counter wargame, with a map depicting the northern coast of the island.

German airborne units were placed in a landing hex, after which a die was rolled and the counter was placed in its final landing hex using a drift diagram, as shown below.

Drift diagram for Air Assault on Crete (image from BoardGameGeek)

The die modifiers due to nearby Anti Aircraft guns always seemed very realistic to me. The non-symmetric drift diagram implied prevalent winds. And surely, given the reputation of Avalon Hill games, this whole procedure was what could be expected in a serious wargame.

Space Marine and Featherstone

I think it was in an issue of White Dwarf during the early 90s, when I read rules involving drop pods for the 6mm game Space Marine. To place the pods on the table, one had to drop paper chits from a certain height above the gaming surface, and wherever the paper chits landed, that was the location of the drop pod. The flimsy pieces of papers would "flutter" down, making the exact landing point quite unpredictable.

I still remember being surprised by such a procedure. Surely the sophisticated wargamer would not use such a "stupid" rule? This seemed so different compared to the almost precise analysis of the drift diagram in Air Assault on Crete, that I didn't realize this procedure was just another randomizer, albeit an analogue one instead of one involving hexes and dice. I could have settled for a mechanic involving a D12 clockface direction for deviation and a 2D6 for distance, as was used in some other GW scattering procedures of the time. But dropping pieces of paper?

It was only much later when I learned that this mechanic had a long history in miniature wargaming, and was described in Donald's Featherstone book Wargaming Airborne Operations (published in 1977, and reprinted by the History of Wargaming project. My version is the American version printed in 1979).

In the book, a few suggestions for airborne deployment are listed:

• Dropping paper chits, but some chits can be heavier, simulating a more accurate drop (e.g. pathfinders that have to lay out the drop zone for the subsequent lifts). Featherstone even suggests dropping the markers with the lights out for night operations!
• A number of adjacent virtual tables to the real wargaming table, on which the troops land. The move towards the central table on subsequent turns.
• Moving a model airplane attached to strings across the table, while the paper chits fall out - although it is suggested it is far simpler simply to drop the paper chits from a box.
• The chits can be color-coded or bear an ID to see what troops have landed where.
• Various dice rolls are suggested for troops being wounded upon landing, or what to do when troops land in difficult terrain. Chance cards are mentioned as well to determine the height of the drop, deviation by winds, etc. 

Dropping paper chits above the table is great fun, and I have used it in various games set in various periods (WW2 to Scifi). Chits that don't land on the table mean the corresponding figures enter the tabel a few turns later, representing troops that were dropped outside of their designated landing zone and needed some time to get back to the main area of operations.

Dropping paper chits from a model airplane (attached to a string for the photograph). From Wargaming Airborne Operations - Don Featherstone

Dropping paper chits from a box. From Wargaming Airborne Operations - Don Featherstone

Scattering

An alternative is to use a scattering die roll, that indicates deviation from a chosen landing point. One can use a D12 die for direction, and 2D6 for distance, or something similar.

On my gaming table, I often use Kallistra hexes. The designated landing point is a hex, and then a D8 is used for devaiation. A die roll of 1-2 means that troops land in the hex, 3-8 indicate the 6 adjacent hexes. When using a D20, one can include a 2nd concentric circle of hexes as well.

 Depending on circumstances (wind, anti-aircraft, height of drop), modifiers to the die roll can be used to make the drop more accurate.

Off-table Landing Zones

The problem with dropping paper chits is that they land all over the table, and that the resulting combat becomes very chaotic, especially on a small table combined with long weapon ranges. The whole idea of regrouping your troops before engaging the enemy is very difficult to play out under such conditions.

Therefore, my preferential airborne mechanic is to use off-table landing zones. The sketch shown below, (taken from my notebook, listing all the games played in my wargaming room), illustrates the basic idea.

Various landing zones are drawn around the table, in two concentric circles. If you look at the right-hand side, zones A, B, C, D and E are adjacent to the table, and zones  I and II are one step further.
Each squad that landed in this scenario was allocated to a single landing zone. A die roll of 1, 2 or 3 indicated the unit landd in the designated zone, otherwise it landed in an adjacent random zone (possibly on the table, and then troops would be placed along the table-edge). For determing a random adjacent zone, simply roll a D6, and start counting from a designated starting point. If there are less than 6 adjacent zones and the die indicates a non-existing one, roll again.

Once the game has started, movement from zone to zone (or onto the table) takes 1 turn. Troops that are on the table can never return to any of the landing zones.

The specific diagram was drawn based on the map for the main table, with a railroad and road delineating various sectors, and a river splitting the table in half. If a different lay-out is used, the zones and connection between them should of course be redrawn.

Using such a diagram provides the player with some interesting tactical decisions. Landing zones for various units have to be decided, and at the same time, the mechanic also provides for deviations during the landing using an easy die rolling procedure. Once all landing points have been determined, various regrouping moves (on or off-table) can be spent before the assault on the actual objectives is started.

Paper airplanes

I once considered paper airplanes that would glide elegantly onto the table, but the dimensions of the typical wargaming table do not make this very practical. However, for a wargame in the outdoors, this might be a fun alternative.

Addenda

1. Featherstone's book Wargaming Airborne Operations wasn't the first to mention the idea of dropping paper chits. His book Air Wargaming (1966) describes the same idea, and the idea has been mentioned in WRG's rules  Armour and Infantry 1925-1950 (1973) as well. I will delve a little bit deeper in my wargaming library to look for older references, but if anyone can find any, please let me know!
2. The boardgame Memoir 44 has a mechanism to drop plastic figures onto the hex-gridded gaming board.
3. When dropping paper chits, you can also line them up on a wooden ruler, and then flip the ruler over, recreating all paratroopers jumping in sequence along the flight path of the carrier aircraft.
   The same idea can be used when using scattering diagrams on a hexgrid, by plotting the flight path along a series of hexes, and having troops jump out in subsequent hexes along the path, each jump followed by a scattering procedure. The game Starship Troopers (Avalon Hill, 1976) used this mechanic, as is shown in the diagram below.

Scatter and flight pah diagram (Starship Troopers rulebook, 1976)

Situational vs Inherent die roll modifiers

Many wargaming procedures involve dice to resolve combat or test morale, and many of these dice rolls come with a list of modifiers. Typically, a die roll modifier adds or subtracts some factors to the roll, and affects the target number to beat a certain result - whether a number in a table or an opposing die roll.

When you look at older rule sets, one often encounters huge lists of modifiers. I often wonder whether such rulesets were playable at all. Below is an example from a seventies-era ruleset. Modifiers are determined not only based on a certain condition, but also on troop type. Unworkable, if you ask me!

Die roll modifiers from a 70s era ruleset. Cross reference the troop type (A, B, ...) with the situation to get a modifier to apply to the die roll. These are only the positive modifiers. The ruleset had a similar table for negative modifiers!

When writing wargaming rules, there are several things to consider when selecting die roll modifiers:

1. Are modifiers situational or inherent? 
2. What is the purpose of the die roll modifier?
3. How many modifiers per roll?
4. How significant should the modifier be?

Are modifiers situational or inherent?

A first type of die roll modifier models a variable (possibly based on historical record) reference for the specific action. E.g. one might have a specific procedure for determining the casualties due to firing, but some troops are of better quality, hence, they get a positive modifier when they fire at the enemy. I would call such modifiers inherent modifiers. They depend on troop characteristics, and are used to introduce variability between troop types.

A second type of modifier represents situational circumstances. E.g. a unit in cover might get a positive modifier when being shot at, or troops uphill get a bonus in melee, or charging gives an advantage to the attacker. Such modifiers depend on the tactical situation in which the troops are placed. They typically do not depend on troop type, but on the situation in which the troops find themselves. I call them situational modifiers.

Sometimes you have a mix between both types. E.g. in a Napoleonic game, a modifier might state that lancers have an advantage on combat, only against infantry in line or square, but not against other troop types. Such a modifier is inherent (lancers), but also situational (target must be infantry in a specific formation). So the distinction is sometimes hard to make.

What is the purpose of the die roll modifier?

Mechanically, the purpose is clear: to increase or decrease the probability of a die roll succeeding, and affecting the outcome that is linked to the die roll.

But a more important factor to consider is whether the modifier affects the decisions made by the player, or simply adds some variation to the die roll procedure (sometimes called chrome). The latter can be fun, but often slows the game down, and might give a false feeling of realism (after all, a huge list of modifiers implies the rules designer knows his history, right?). The former is - at least in my view - a much more important effect of die modifiers: do they steer the decisions made by the player?

I do think that the true purpose of modifiers should be to influence decision-making during the game. Hence, situational modifiers are preferred, and inherent modifiers to be avoided. After all, you can decide whether to put troops in cover or on a hill, but you cannot decide that your cavalry suddenly becomes equipped with lances, or is better in morale. At most you can decide where to deploy certain troop types before the game starts, but that's a pre-game decision that is different from a tactical decision in-game.

That does not mean one cannot make a distinction dependent on troop type, but it should preferably be reflected in the troop characteristics, rather than in the modifiers when resolving a die roll.

How many modifiers per roll?

If we want modifiers to guide decision-making, I think they should be limited in number such that a player can learn them by heart, rather than having to look them up in the rules all the time. Too many modifiers will simply result in a lot of random number-adding, ending with an overall +0, +1 or -1 anyway.

3 or 4 modifiers per procedure seems to be a good number. It allows players to remember them, and make each modifier significant enough such that they do not get drowned out by other effects.

I know it can be fun to distinguish between all sorts of cover, but does it really matter (unless the game considers it at the heart of its gaming engine)? Simply use one type of cover with a single modifier, and that's it. Limiting the number of modifiers to a significant set that influences actual decision making is part of designing the rules. Playtesting also might give you insight what modifiers players will use actively in their choices during the game, and what modifiers are just chrome, and subsequently, can be tossed. Also, modifiers that describe situations that are so exceptional that they happen only once during an entire game, should be avoided as well.

How significant should the modifier be?

Modifiers should also be significant. A +1 modifier on a D100 is not going to actively influence decision-making.

Some time ago, we had a discussion in my gaming group when playing a recent set of rules that used a 2D6 die roll to activate units. Most units needed a 5+, 6+ or 7+ to be activated, with 6+ being the most common number. However, none of the players felt that having 5+ or 7+ troops guided their decisions. Rather, it was the tactical situation on the field that drove the decision what unit to activate next. Thus, the activation rolls can as well be set at 6+ for all troops (it saves time!); or should be spread out to 4+, 6+ and 8+ if we want to give them a meaningful role in the game, such that the differences in probabilities become significant enough for the player to cosnider them. Modifiers should mean something, not simply add some random noise!

To conclude ...

Overall, I think that modifiers are an important aspect of game design, and it does matter what the intent is. If the intent is simply to add chrome, go wild, add lots of modifiers reflecting all sorts of different things!

But if the intent is to guide decision-making, better limit yourself to situational modifiers, keep them limited in number, and large enough in effect.

Addendum

There's some follouw-up discussion on this thread on The Wargames Website.

Some thoughts on the turn sequence

When discussing wargame mechanics, the turn sequence is often a subject of hot debate. In a sense, the turn sequence is the engine that drives the game forwards. Many other mechanics that deal with combat resolution or morale, are often embedded in the overarching turn sequence. The turn sequence regulates the alternating role of players, but also regulates the order in which units can act and how.

The classic IGO-UGO turn sequence

During the early days of wargaming, the turn sequence was rather simple, and is now often referred to as an “I Go, You Go” sequence (IGO-UGO). Both players take alternating turns, and within a player’s turn, the order of actions (or phases) is fixed as well. Typically, I move all my units, then I shoot with all my units, then I resolve close combat with all my units, then I resolve morale for all my units, and then you take your turn.

Let’s try to put this in a diagram. Let’s assume we have 2 sides (Red and Blue), and 3 units per side (A, B and C). A complete cycle starting with Red would mean that Red moves all of his units first, then shoots with all of his units, and so on. The fixed order in which all activities take place can then be schematically represented as follows:

	Movement	Firing	Melee	Morale
Red, unit A	1	2	3	4
Red, unit B
Red, unit C
Blue, unit A	5	6	7	8
Blue, unit B
Blue, Unit C

 
The matrix above lists all possible phases for all possible units, and the numbers indicate in which order they are executed. It is a very straightforward turn sequence, and one that is still present in many wargaming designs. It is also a traditional way to play classic boardgames, such as Monopoly, Snakes and Ladders, even Chess. They all follow a similar format:  move a piece, then do something with that piece. If you follow that framework, it is quite natural that you end up with this particular turn sequence. BTW, you also often see this same turn sequence appearing in board wargames. The Avalon Hill classic hex-and-counter wargames also use the framework “move all of your pieces, then do something with them.”

The main problem with this turn sequence is there is no possibility for the opponent to react, or to do something with his troops. The classic example is so-called overwatch fire. When I move my units from one covered position to the next, you cannot shoot at my troops, although they might be vulnerable during some  part of their movement path. Another often-cited problem is that I can have a unit outside of our mutual firing ranges, I move them within range, and I blast your unit to smithereens before you have the chance to do anything.

Solutions often come in two forms: re-order the various phases of the turn, and/or introduce more sub-phases. Re-ordering is the more elegant solution. The sequence might then involve that Red moves first, then Blue shoots, then Red shoots, then a joint melee phase occurs, etc. Another often-used solution is to put the firing phase before the movement phase, such that “move and shoot to smithereens before you can do something”-tactics are not possible.

Adding more sub-phases, sometimes depending on troop-types, becomes complicated very rapidly. It results in games in which you have various movement and firing phases for each side, sometimes interspersed. In my experience, these do not play fluently, since players often not capable remembering what troop type can do something in what phase.

Any turn sequence also has implications for the underlying mechanics of the various phases, and how these phases influence each other. E.g. the morale phase might specify conditions and events that happened in the previous combat phase. A strict ordering of phases makes such interactions more easy to deal with, but also has to allow for “out of order” actions that otherwise do not fit the overall structure. E.g. when charged, troops might be allowed to counter-charge or run away, although it is not strictly their movement phase. Similarly, movement reactions often are part of the morale phase as well.

Alternating unit activation

In this turn sequence, players alternatingly activate units. Red activates a unit, then Blue activates a unit, then Red activates another unit, etc., until all units have been activated. Each player chooses what unit to activate next, and some sort of bookkeeping is needed to remember what units already have been activated. During a unit’s activation, the unit can move, shoot, fight, etc, but not necessarily in a fixed order.

We can schematically represent this turn sequence as shown below, with Red activating unit B first, then Blue activating unit A, followed by Red activating unit A and so on.

	Movement	Firing	Melee	Morale
Red, unit A	3
Red, unit B	1
Red, unit C	5
Blue, unit A	2
Blue, unit B	6
Blue, unit C	4

As you can see, during a full cycle, all units still get to do all possible actions, but we have organized them in a different manner. If you are familiar with computer programming, you could see this as having two loops turned inside out. The classic sequence looped over all phases, and each unit got an action during each phase. This sequence loops over all units, and a unit gets to do all phases when it is selected. Another way to look at it is that we subdivided the matrix listing all possible actions for all possible units by rows instead of by columns.

This sequence has some consequences on the mechanics of the various phases. The mechanics of a phase cannot be strongly dependent on previous phases or the actions of other units. E.g. it becomes more difficult to have a morale phase that would take into account the actions or behaviour of nearby units.

This turn sequence is often more flexible in design than the classic sequence, since the phases themselves do not form the overarching structure of the game. Hence, it is easier to add new types of actions or phases that a unit can do. Suppose you would like to include an engineering activity in your game. The classic sequence might make this part of the movement phase – or should introduce a new "engineering phase" in the turn sequence. The alternating unit activation sequence can simply add a new type of activity that a unit might or might not do during its activation. It might seem like a subtle difference, but it works very well in e.g. roleplaying games in which each character takes a turn, and can then do a multitude of different actions available to the player.

Variants on alternating unit activation

To ensure an equal pacing of units being activated on both sides, variants often include that whatever sides has the most units left to activate, must activate the next unit. Group activations are another variant that can guarantee multi-unit coherency.

Another, more extreme variant stipulates that players cannot choose what units to activate. Often, this is implemented as some sort of draw (cards, chits, …) with each card specifying what specific unit can activate. This is not a very attractive mechanic, because it takes away important decisions that the player wishes to make. Moreover, in some scenario setups, it can clearly create bottlenecks, when e.g. a column of troops has to cross a bridge, and units simply refuse to be drawn in the correct order.

A hybrid is possible, by allowing a randomization to check what side can activate, but then leave the decision up to the player to determine what unit will activate. Such mechanisms also often include the early abortion of the entire cycle, such that neither player is certain that all his units get to be activated, and is forced to activate those units first he thinks are most important. Underlying mechanics to accomplish this often include special cards in a deck that drives the alternating activation sequence.

Unit-driven IGO-UGO sequence

This turn sequence tries to combine the best of both worlds, by using the alternating player structure of the  IGO-UGO sequence, but within each player’s turn using a unit activation mechanism. This is a turn structure that has become very popular in modern designs. During a player’s turn, the player can choose which units to activate and in what order. Often, dice control the activation sequence (command rolls), or a hand of cards might drive the player’s choices. An early abort mechanism often is included as well.

The following diagram illustrates this sequence, with units in grey not having activated due to an early abort, e.g. a failed die roll. First Red activates unit A, followed by B, and then fails to activate further units. Then it's Blue's turn, activating unit B.

	Movement	Firing	Melee	Morale
Red, unit A	2
Red, unit B	1
Red, unit C
Blue, unit A
Blue, unit B	3
Blue, unit C

The advantage is that the mechanics for the different phases (movement, shooting …) can still be interlinked, since we can assume that a large number of units will get activated within the player’s turn. Hence, it might be possible to sequence the movement unit by unit, but still keep an overall morale phase at the end or the beginning of the player's turn.

Random phase sequence

The advantage of using the matrix representation to illustrate the turn sequence is that you can subdivide the matrix in different ways (i.e. organizing the turn in rows or columns as shown before), but one can also re-arrange the columns in random order.

An unusual turn structure might therefore randomize the different phases over all players. Thus, we could first have Blue firing, then Red movement, followed by Red morale etc. As a mechanic, this can be easily achieved by making a custom card deck and drawing cards to see what next phase comes up. The diagram below illustrates a possible random sequence.

	Movement	Firing	Melee	Morale
Red, unit A	2	8	6	3
Red, unit B
Red, unit C
Blue, unit A	4	1	5	7
Blue, unit B
Blue, unit C

Such a sequence requires that all phases can be resolved independently, as explained before. I have only tried it once before, in a skirmish game in which many unexpected events might take place, and an emphasis is put on heroics rather than a coherent well-orchestrated battle plan.

Conclusion

There are of course many more turn sequences possible. All sorts of hybrid formats can be imagined. In the end, the turn sequence is interlinked with the underlying mechanics for the different phases and activities, since the entire gaming engine has to form a coherent whole.

As a games designer, it’s always useful to tinker with various ways in which the turn can be organized. Even if you end up with a classic IGO-UGO sequence, at least you thought about it and can defend your particular choice much better.