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.