So, one of the things that is germaine to just about every wargame is the way it handles the passage of time. This occurs on a couple of different levels, depending on the wargame. First, there is the passage of time for the simulated inhabitants in the wargame - how much do they get to do during the passage of simulated time? But, more importantly, is the passage of time (real world) for the game it self. By that, I mean to ask, how are the actions that the players are taking - moving the pieces, engaging in simulated combat, and so forth? This is usually divided up into some mechanism where either both sides (or all sides) do their actions more or less simultaneously, or they take turns doing their actions. In both cases, regulating who goes when is done by a number of different mechanisms that we can look at, and call Initiative.
First, the treatment of a wargame as a classic two player game of conflict, where the players take turns, and during a player's turn does all the allowable actions, is often referred to as "you go, I go" type initiative. This is the way it is done in many board based wargames, and has a long history going back to the abstract wargames of antiquity (such as Chess, Chatauranga, and Hnefetafl). I have heard it commented that this is a natural way to view elements in a battle, even if it is implemented a little artificially in a game. The idea, within a battle, is that there are a series of actions that then get reacted to, forming a sort of rhythm.
Determine who gets their turn involves initiative. The simplest manner is to determine the order (which is player A going first, and which is player B going second) during the first turn (which may be by a dice toss, or agreement, or set by a scenario) and then following that throughout the game. We can call this a "regular, alternating initiative". The turn sequence (with two sides in the scenario, Red and Blue, taking turns in the sub-turn role of Player A and Player B) would look like this
Regular Alternating Initiative
Turn 1
Player A - Red
Player B - Blue
Turn 2
Player A - Red
Player B - Blue
Turn 3
Player A - Red
Player B - Blue
A variant would be to, at the beginning of each turn (which consists of two sub-turns - one for each player), randomize (dice or cards) to see which is player A for that turn, and which player B. We can call this a "random, alternating initiative". A feature of this is that there is a chance that the same side does not go first every time. However, one of the side effects of this is that it is possible for a side to get to go twice in a row (in fact, it is guaranteed that this will happen, if the order does change). See this example:
Random Alternating Initiative
Turn 1 - dice toss, Red wins
Player A - Red
Player B - Blue
Turn 2 - dice toss, Blue wins
Player A - Blue
Player B - Red
Turn 3 - dice toss, Blue wins
Player A - Blue
Player B - Red
Now, for the "feature" of this method, you can see that between the end of Turn 1, and the beginning of Turn 2, the Blue side goes twice in a row. In a game with a large number of turns, the rules of probability would tend to balance out this effect, however in a game with only a short number of turns (say, 3,4,5 or 6 turns) it might provide a very large benefit to one side or another, depending on how the randomizing turns out.
Each turn in a "you go, I go" type game itself typically has several phases, that allow for the ordering of the activities to get done. These might include - issuing orders, movement, shooting, melee combat, morale tests, artillery - and so forth, depending on the type of combat that is being simulated. A very common variant of the "you go, I go" type game is one where those phases get mixed up.
The turn (and phases) of a game with "regular phases" might look like this.
Regular Phase Turn Structure
Turn
Player A
1. Shooting
2. Movement
3. Combat
4. Morale Tests
Player B
1. Shooting
2. Movement
3. Combat
4. Morale Tests
When some of the phases during a Player Turn actually belong to the side that is taking the role of the Non-Phase Player, we see an intermixed phase structure. A good name for this sort of turn ordering is Intermixed Phase Turn Structure.
Intermixed Phase Turn Structure
Turn
Player A
1. Player A moves units
2. Player B shoots
3. Combat
4. Morale Tests
Player B
1. Player B moves units
2. Player A shoots
3. Combat
4. Morale Tests
Typically the point of having a Intermixed Phase structure is to introduce some elements that allow for each side to react to some of the actions of the other side. In the above example, what is being replicated is the reaction of units to shoot at the enemy as they see them getting closer. Depending on the simulation intent of the rules writer, this sort of structure will help them bring out what they think is important for the aspects of combat that their rules represent. One of the most common ways that this is done (perhaps inadvertently) is that during Combat, most wargames allow both sides to score casualties - so that both sides are operating more or less simultaneously during a combat phase).
An alternative to "You go, I go" is something that we can name "We go" - this means that there is a turn, divided up into Phases, but during each phase there is a structure for determining who goes first. This can be either Regular within the turn (meaning that the same side goes first for each Phase), Regular across turns (meanign that the same side goes first each Phase, and this is the same every turn), or some combination. As the two players are alternating within a phase, but that the phases are being executed more or less concurrently, this can be named Alternating Order, Phase Concurrent Initiative (either regular or random, intermixed or not). A turn structure here might look something like this:
Alternating Order, Phase Concurrent Initiative
Turn
Phase 1 - Movement
Player A moves
Player B moves
Phase 2 - Shooting
Player A shoots
Player B shoots
Phase 3 - Combat
All contacting units combat
Phase 4 - Morale
All units requiring tests take them
An alternative to this scheme is to have regular Phases, but to have randomized activity order within the Phase - perhaps by dice or unit quality or by the turn of a card. A common version of this are rulesets based on the structure of The Sword and the Flame - there is a Movement Phase, a Shooting Phase, a Combat Phase, and a Morale Phase. But within the Movement Phase, cards are used to determine which units move before other units. The same is done during the Shooting Phase. Combat (hand-to-hand) and Morale are done in preset orders (either by the order in which they arose during the movement phase, in the case of Combat, or all simultaneously in the case of Morale). Such a turn scheme might be accurately labeled Randomized Order, Phase Concurrent Initiative.
Randomized Order, Phase Concurrent Iniatiative
Turn
Phase 1 - Movement
All eligible units may move, randomized order based on flipping cards
Phase 2 - Shooting
All eligible units may shoot, randomized order based on flipping cards
Phase 3 - Combat
All contacting units resolve hand-to-hand combat in the order in which they contacted during Movement.
Phase 4 - Morale
All units test morale simultaneously
The most common alternative to the Alternating Order, Phase Concurrent Iniative scheme (which is really quite popular in a lot of rulesets, especially those representing time periods where the interplay of space and time are important, such as when movement and shooting combine to have a big effect on the combat) is to have the Phases actually structured so that they are as close to Concurrent themselves as possible. This would be a Simultaneous Order, Phase Concurrent Initiative. What this structure seeks to do is to remove any advantage for going first. It is not perfect, especially in the area of movement, without the use of some blind method for plotting movement ahead of time (such as writing turn by turn movement orders, and having them interpreted by a referee. Many players, especially modern players, find this unsatisfying, because they want control over where their units move.
A typically scheme employed here is to use a "test" - usually a dice test - to see how the individual troops will react to situations that arise out of the simultaneous activities of the players. This replicates the effects of command and reaction by the troops, at a level of command lower than what the player is exerting. For instance, a player may tell a unit (a battalion? perhaps) to move ahead. In this situation the player may be taking on the role of a Brigadier or Division Commander. But as the battalion moves ahead, it finds itself the target of a charge. The Battalion commander in real life would rely on personal initiative and training in order to decide what to do next. This might be to fire on the chargers, form square, withdraw, adopt skirmish formation, or whatever. The rules would try to anticipate these types of situations, and enable a dice test for a unit to try in order to see if they can do these things. This structure is often included in all of the different initiative types presented here, but it is especially important in the simultaneous phase execution type game.
A Simultaneous Order, Phase Concurrent Initiative turn example might look something like this: (Note, to illustrate the dice test mechanism, I have separated out Charging from normal Movement)
Simultaneous Order, Phase Concurrent Initiative
Turn
Phase 1 - Charges
Both players declare charges simultaneous
Both players move charging units
Units targeted by charge may roll reaction to countercharge
Phase 2 - Movement
Both players move units that did not charge, and were not contacted
Phase 3 - Shooting
Units that did not move or charge may shoot (even if contacted)
Phase 4 - Fighting
All units in contact resolve hand-to-hand combat
Phase 5 - Morale
All units requiring test for fail or recovery
Another theme popular in rule sets is to have the phases occur, in order, for a part of a side (either an individual unit, or perhaps a group of units such as a battle group or a brigade), but to have those parts be either randomized or alternate. Once such a "part" is activated (whether a unit or a group of units), it will do it's allowable phases - movement, shooting, combat, etc. Then the next "part is activated. The ordering here is done either on a regular bases, where alternation between sides is common, or it is randomized perhaps by dice toss to determine regular order at the beginning of a turn (such as in Shako II, where you roll an "initiative dice" to determine the order of divisions at the beginning of each turn), or by the flip of a card (such as in rulesets where you have a card for every brigade in the game, and those are shuffled at the beginning of a turn, and then revealed to see which brigade does its actions first). These two different initiative schemes can be called, respectively, "Regular Order, Phase by Command" and "Randomized Order, Phase by Command" - where the 'parts' are referred to as the "Command". Here is an example of the second scheme.
Randomized Order, Phase by Command
Turn
Reveal a Card, identifying a Brigade
Brigade performs all of the following Phases
Phase 1 - Movement
Phase 2 - Shooting
Phase 3 - Combat
Phase 4 - Morale
Next Card
This scheme can vary by allowing for the intermix of other phases, for enemy units encountered on the table top (such as reaction moves, reaction fires, counter charges, etc).
When there is a basic "You Go, I Go" structure (even with their variations, these are the simplest to implement, and the simplest to explain in written rules), sometimes the unnatural regular alternation of moves is controlled by a dice roll (or some other method, such as commander's value or army effectiveness, etc). In this case, the dice roll will determine how many actions may be done in one or several of the phases of the turn. For instance, in the DBA family of games, a dice for command points will determine how many "commands" (consisting of one base, or a group of connected bases) may move during a turn. They move, and then shoot, and then all in contact fight, and the turn is over. Not every unit gets to move (or shoot) each turn. This scheme is applied, in different rule sets, to almost all of the various initiative schemes presented here so far.
The Piquet family of miniatures rules mixes up this ordering one more way. In those rules, it is common to have a Turn consist of a number of different Actions (regulated by some counter, called Initiative Points among other things). Once those actions are all used up, the turn is over. In Piquet, there is a mechanism to see how many of those actions a Player gets to use at one time, based on opposed dice rolls by the different sides. The higher of the dice tossed gets to go, and he gets the difference in initiative points. How the player gets to expend those initiative points is based on a randomized presentation of options. In Piquet, it is a card, showing a single type of action (move, shoot, reload, etc). The player may expend as many actions as desired on that single type of action, and then flips the next card to see what else may be done. Eventually the player runs out of points, and the next opposed dice roll is made.
Another variation to the many different schemes related to "You Go, I Go" is one where a player may decide to "steal the initiative" from his opponent. In this case, one of the two players is determined to have the Initiative - in other words, it is that player's turn to execute phases for his forces. The other player (through a number of different possible mechanics - expending command points, rolling dice, flipping cards) may try to "steal the initiative" - meaning that they get to execute phases for their own forces instead, trumping the actions of the first player. In order to be fare, such a scheme is often structured around some penalty for the player attempting to steal the initiative. In addition to the "You Go, I Go" type turns, this variation is also common in the Phase by Command type schemes - where it becomes the turn for one Command (brigade, squadron, wing, etc) to do their actions - another player may decide instead to attempt to steal that order for one of their own Commands. If successful, then the turn changes to the new Command, but if not successful, then there is often a penalty for that other Command (such as, it may not go this turn, or the player loses one of a finite group of command points, or something similar).
A recent, but popular variation of "You Go, I Go" is one where within the turn structure of a Side, that side gets to make leadership tests to see which of his units (or Commands) gets to act, and how much they get to act. Penalties arise from failing the leadership tests required to get units to act (for instance, after so many failures, the turn may pass to the other player, or again, finite command points may need to be expended in order to 'try again'). This scheme is in the recently family of miniature rules sets coming from the Rick Priestley school of design, starting with Warmaster, and also seen in the Warlord Games family of titles (Black Powder, Hail Caesar, etc) and the Blitzkrieg Command series of rules. It works very well, and puts the emphasis of command decision on the player, but with the uncertainty of a dice roll involved in order to carry out the desired orders. Very effective design.