The Four Main Principles of Combat Casualty Selection

Today I’d like to discuss something that most Axis & Allies players take for granted: casualty choices made during the Conduct Combat phase. With combat–especially naval combat–approaching a new height of complexity, and with the recent explosion of new unit types and abilities, one’s choice of casualties is becoming more nuanced and complicated than ever before. Understanding the basic principles behind the various casualty choices that players can make will, I believe, help guide both novice players and experienced players who have come to rely on faulty doctrine toward tighter decisions in the combat phase.

The Six Phases

Generally, people think about Axis & Allies in terms of phases: the six phases that, taken together, encapsulate all the permissible actions that constitute the game. These phases vary slightly with each published version of the game, but the most recent iterations are: (1) Purchase & Repair Units, (2) Combat Move, (3) Conduct Combat, (4) Non-Combat Move, (5) Mobilize New Units, and (6) Collect Income. With the exception of #6, which is, for the active player, a simple mechanical calculation of accounts due, each of these phases is a potential repository of meaningful choices for the player. Since the game is played in accordance with these phases, the majority of which are important reflections of in-game choices we make, this is a natural and obvious way to conceptualize it.

Conduct Combat: A Sense of Futility?

There is occasionally a sense of helplessness, disaffection, or lack of interest demonstrated by some players during the Conduct Combat phase. This is quite natural in those instances wherein one is being attacked by a numerically superior force, and are eliminated in a single salvo [a complete round of the dice rolls of both players] without having a chance to make any meaningful decisions. This, of course, might occur quite a bit in the other player’s turns, as it is generally good practice to deny one’s opponent access to meaningful tactical (in-combat) choices, usually by stacking the odds overwhelmingly in your favor. Very few battles indeed exceed three salvoes, so the mere brevity of combat might discourage active intellectual engagement with the choices it generates. However, since both you and your opponent should always be asking yourselves the question “How many attacks can I initiate this turn without a serious risk of failing at one or more of them?”, there should be plenty of instances in either of your Conduct Combat phases wherein the odds are close enough for the potential for meaningful decisions to emerge. Even players who choose low-risk, low-reward strategies like dog-piling isolated enemy units may still find themselves occasionally surprised by the outcome of the dice rolls. The unpredictability of these rolls keeps both hope alive in the heart of the defender, and fear alive in the heart of the attacker: in other words, it is the element of chance inherent to this mode that makes the game exciting and emotionally involving for players. This is one reason that low-luck or no-luck Axis & Allies variants fail to arouse my serious interest: they prohibit unlikely outcomes that are dramatically satisfying to witness and play through. Though a dice-averse player should probably avoid Axis & Allies in the first place, she ought to take some comfort in the odds that bad luck experienced in one round will be balanced out by good luck in the next. You can lose many single battles without losing the war.

Exclusive Reliance on a Single Casualty Selection Principle: Replacability

Let’s say that you accept my point that the chance outcomes of the combat phase are actually good for the game. Let’s further assume that you don’t feel helpless in the conduct combat phase, or, if you do, that you realize that you can make your opponent feel equally helpless during your attack phase. Even with these caveats, you might think that the process of casualty selection is generally flat and boring, even if the dice results themselves are exciting. This is largely due to the fact that most players employ one main principle–and often only this one–to the selection of casualties in the conduct combat phase: “Where possible, the units with the highest IPC costs should be removed last”, or, equivalently, “The units with the lowest IPC costs should be removed first”. That’s it. Let’s call this the replacability principle, as the main or only consideration as to the order of casualties chosen is how expensive a unit will be to replace. But this calculation is not as simple to perform as it seems on the surface, and there are many instances wherein other considerations will supersede this principle.

While the replacability principle is easy to memorize, and works well enough most of the time (it is especially useful for teaching new players how to play the game well as it is, roughly 85% of the time, exactly the right way to proceed), it does have its faults. First, sorting units by their simple IPC value does not take into account many factors which may serve to effectively modify their value: location, for instance. A US battleship in SZ 10 is worth exactly 20 US IPCs, while a US battleship in SZ 6 is worth more. How much more is a matter open to debate, but I would approximate in excess of 26 US IPCs, because it directly threatens the opponent’s income (via interdiction), shapes their purchasing decisions, and impinges greatly on their potential movements. Thus, when choosing a destroyer or a fighter as a casualty, the calculation of replacability shouldn’t be as simple as “The destroyer is the cheaper unit, therefore the destroyer is the logical choice”, but also considerations about how troublesome it would be to get another destroyer that far out from your industrial complex. It may turn out that in terms of true replacability, it would be ‘cheaper’ to take the fighter off as a casualty and keep the destroyer in enemy territory hunting down their subs.

[As a side note, this is one factor which makes defending economically advantageous in the game: as your opponent approaches your factories, each of your units’ value increases dramatically in terms of their potential utility, because as soon as they are placed on the board they are put in the line of fire and thus get to roll their allotted dice; while your opponent must spend some valuable movement time to get their units into that position. In other words, your 8 IPC destroyer has a chance to immediately destroy your enemy’s positionally value-enhanced 14 IPC destroyer: while you can replace your destroyer in the same SZ next turn, it will take your opponent another three turns to build and move her destroyer back to the same SZ. On paper, you are both spending the same # of IPCs for the same value of units, but this is deceptive. Of course, if you’re this deep on the defensive, you’ve probably lost a good deal of territories, so this factor in and of itself can never, on its own, swing games against an attacker. The fact that infantry are cheaper than transports, tanks, and bombers might, however.]

Alternative #2: Pips Principle

A second casualty selection principle, the pips principle, considers the value of a unit to rest solely on the number of die pips it contributes to the battle at hand, regardless of whether it is a defensive or an offensive battle: “Take the units with the fewest pips off of the battle board first”. While this principle generally aims at maximizing enemy casualties, and thus at winning a particular battle (which, of course, ties in perfectly with the greater overall goal of winning the game), it also has some shortcomings. Taken in isolation, the pips principle would advocate taking the first hits off attacking aircraft carriers, because they contribute literally no pips to the battle. However, if aircraft carriers take hits, they cannot have planes land on them (at least not for a turn), which means that the defensive pips of the air units will be shaved off of future sea battles (and, of course, the planes might not even be able to land after a successful attack, if you’re in an empty sea zone or off of an enemy territory). The pip principle thus ignores the interrelatedness of present and future combats, as well as the replacability principle (although the two are usually in accord, due to the general, but not universal tendency of units with higher costs to have higher pip values). The destroyer / fighter choice scenario mentioned above also applies here, as a fighter has 3 pips on the attack as compared with the destroyer’s 2. Nevertheless, if you need a destroyer post-combat to clean up enemy subs, then reliance on the pip principle will lead you as far astray as simple reliance on the replacability principle: the fighter must go, number of pips be damned.

Alternative #3: Hardiness Principle

In combat wherein victory is immanent, but a counterattack in the same space is predictable, the hardiness principle comes into play. This principle takes for granted that the battle will be won by the current attacking units, and instead concentrates on selecting casualties based on how well these units will perform on a future defense. Instances of this include killing a bomber instead of an infantry on the last round of combat in order to better protect that space against the enemy. The hardiness principle can be seen as a future-oriented variation of the pips principle, but is importantly distinct because applying these two principles at the same time will offer differing casualty recommendations. In an attack against an enemy tank with a bomber and an infantry, the pips principle will always recommend taking out your bomber last–even if that means you don’t capture a territory you actually need, like a capital or victory city, or a national objective. Let’s say that in this sample battle you hit the enemy tank on the first salvo, and it hits back. At that point, the hardiness principle would recommend taking the bomber off instead of the infantry, because the infantry will do better in holding off potential counterattacks.

Alternative #4: Mobility Principle

Finally, there is a fourth main casualty selection principle: the mobility principle. If you’re fighting distant enemies, or enemies in many different surrounding territories or sea zones, you might find that it’s not the cost or the combat effectiveness which shapes the units you purchase and choose to conserve in combat, but those that are able to cover the most board spaces possible, and thus give you maximum flexibility in your potential initiatives and responses. Aircraft are generally the most versatile and mobile units from such a perspective, as they can strafe behind the lines on land, and have great reach at sea as well, especially with the aid of aircraft carriers and/or air bases. Sea units are typically second in terms of mobility, though occasionally they will outperform air units in terms of reach, especially if aided by a naval base. Take, for instance, a navy occupying SZ 33, surrounding the Caroline Islands naval base: if there are transports with land units available there, the victory cities of Honolulu, Sydney, Manila, Shanghai, and Tokyo can all be threatened simultaneously–a feat of mobility that most air units in the same position simply could not achieve due to their need to land in a previously-owned friendly territory.

We have seen, then, that there can different alternate principles of casualty selection in combat for every attribute a unit has: cost, movement, attack / defense values, and special abilities. Without getting into too detailed a series of explanations, if you require a unit’s ability to blitz, bombard, strategic bomb, torpedo attack, or even capability of taking over enemy territories, then it may be exempt from every principle of selection mentioned thus far. Even ‘fitting on available transportation’ might be considered a special ability in some instances. Consider a battle wherein you have two tanks and one infantry battling a small enemy force on land. If you receive a casualty, you might choose to destroy a tank over an infantry if there is a lone transport hovering in an adjacent sea zone and you have an amphibious assault planned for the next turn, because while an infantry can fit on that transport with a surviving tank, the other tank cannot.

My point is not that every principle is flawed or incomplete, but rather that by applying each of these principles in turn to particular combats, as filters, the chance of making a better choice of casualties is increased dramatically. Let us take some concrete examples of when various principles might be applied, and exceptions to these.

Special cases

Transports must be chosen last. Thus the only meaningful choice regarding these, and this will happen only rarely, is if you’re given the choice to sink loaded vs. unloaded, or differently-loaded transports (say, in a naval attack gone wrong where you can retreat 1 transport to safety and choose the other as a casualty). This is one of those relatively straightforward cases where it seems most plausible thing to do would be to choose on the basis of the cost and/or pip value of the loaded land units (excluding the tricky choices surrounding AA guns, which causes some wrinkles even in this choice).

Important territories (often) ought to be taken, and if possible held. If I am attacking Moscow as the German player with 3 infantry, 3 tanks, 3 fighters, and 3 bombers, then the replacability principle is out the window: nothing will need to be replaced if I win this battle, and thus–most probably–the entire game. I will probably employ the pips principle until I am certain of a win, and then turn to the hardiness principle. Even before I am certain of a win, however, I will take off fighters rather than tanks in all instances, even though they are more expensive, more mobile, and defend better. This is not only because tanks have the ‘can take over land territories’ ability, but also because fighters–known for their exceptional defense values–actually have ‘0’ hardiness where I need it, which is in defense of the capital city I am hoping to acquire. Indeed, in the ultimate, and perhaps even penultimate, salvoes I would start to remove any air units instead of infantry, in order to retain the largest possible land force on the ground.

**_Principles in Practice: Scenarios

Let’s look at a couple interesting scenarios now, to demonstrate how the casualty selection principles we’ve discussed can be used as filters for making good decisions in the tactical mode.

Scenario A:
Japan attacks Malaya by land with 2 tanks and 2 infantry, taking two casualties in the first salvo, and the battle is concluded in its favor. The Japanese player plans to move a nearby empty transport there during the non-combat movement phase, to ship the remaining units from Malaya for an amphibious assault on India next turn. In this case, due to the need to exert maximum force on a major objective, the special ability ‘fits on a transport with a tank’ (which contributes to ‘mobility’) outweighs ‘replacability’, ‘pips’, and ‘hardiness’. So the casualties should be 1 tank and 1 infantry, rather than the 2 infantry choice that most principles would advise, because even though the destroyed tank costs twice as much, adds an extra two pips on the attack, and defends better than an infantry, it cannot fit on the transport with the other tank. The second tank is dead weight, in terms of the next major objective, and should be removed.

Scenario B:
In sea zone 17 surrounding Iwo Jima, a Japanese aircraft carrier loaded with 1 fighter and 1 tactical bomber is being attacked by a lone US cruiser, which hits on the first salvo. In terms of mobility, replacability, pips, and hardiness, at first glance it looks like the first hit ought to be taken off of the carrier. However, the undamaged status of the aircraft carrier allows it to add mobility to the fighter and tactical bomber it carries; as well, the defensive strength of the carrier is greatly impaired when damaged, as its aircraft will have to seek refuge on Iwo Jima and will be unable to subsequently defend the SZ (this is particularly troubling if the UK or ANZAC have units in the area that are in position for a follow-up attack); overall hardiness will be reduced by a total of 7 pips. Since the cruiser is likely to be destroyed by the defending fire, pips for this turn’s defense don’t matter so much anymore. So we can discount the simple pips principle. Indeed, if a follow-up attack that threatens the carrier is possible, then hardiness should be our overriding concern. The simple replacability of a plane is much better than that of an aircraft carrier–10 IPCs vs. 16 IPCs–even though on the first attack it looks like no unit is actually lost due to the carrier’s ability to soak up an extra hit, so no unit will need ‘replacing’, due to the secondary threat it is likely that the carrier will be destroyed if damaged (the calculation depends on the strength of the follow-up attack, and its purpose: if the UK force is huge, then perhaps it would be best to sacrifice the carrier and allow the planes to shelter themselves on Iwo Jima; if the UK will invade Iwo Jima with several transports full of land units, it is better to concentrate all resources to the defense of the SZ and hope for victory there). Finally, in terms of mobility, the planes will be severely hampered in their operational utility without a functional carrier upon which to land, making the planes actually worth less if the carrier is damaged. Thus it looks like the casualty ought to be either the fighter or the tactical bomber: but which ought we choose? Pips still don’t matter to our calculations for the moment; we’re assuming we’ll hit the US cruiser, as our defending rolls [(4+3+2)/6] should generally yield 1.5 hits on average, and we only need 1 hit to kill the cruiser and survive. The mobility of the two units is identical–4 movement points–and thus not a deciding factor. In terms of replacability, the tactical bomber is 1 IPC more expensive: but in terms of hardiness, the fighter is 1 pip more effective. Given the expected counterattack, and that the function of units is essentially to cause enemy casualties–the cheapest of which will be 8 IPCs in a naval battle (an enemy destroyer, as hitting subs isn’t possible for ‘blind’ planes unescorted by their own powers’ destroyers), considerations of hardiness outweigh considerations of replacability in terms of utility. To summarize, the tactical bomber costs 1 IPC more to replace, but the fighter has 1/6 more chance to sink an enemy unit of 8 IPC value: a net utility of 1.3 IPCs, which doubles (or better) with every additional salvo it survives (as it takes even more shots, at even more expensive units). Thus, the tactical bomber is the logical choice of casualties, all things considered.

Conclusion

Contrary to the generally accepted view, the Conduct Combat (or ‘tactical’) phase can, indeed rather frequently does, offer up many rewarding opportunities for clever choices between potential casualties. By explicitly recognizing the principles of casualty selection that we already implicitly employ every time we play the game, we can actually increase the number of salient casualty choices at our disposal, and so lay bare the means by which more careful, rationally-considered–and even surprising–decisions can be made. Good strategic play is, of course, essential to victory in Axis & Allies: but without principled tactical recommendations in combat casualty selections, inefficiency and waste will result; in this manner, initiative can be lost, and ultimately one’s strategic goals may be thwarted.

In my next article, “The Psychology of Conduct Combat Phase”, I will further highlight the importance of the Conduct Combat phase on the strategic workings of the game. I identify typical in-combat A&A behavior and experiences, and show how these can positively and negatively influence one’s planning flow. As well, I offer some strategies for compensating for and overcoming the more pernicious of the psychological distortions and skews that switching between the tactical and strategic modes (as the game requires us to) can produce._**

@MikeMasino:

Well written.  The cheapest naval unit, the submarine, can have a devastating (albeit lucky) effect if chosen last as a casuality, as one successfully nailed my sinking battleship, my last naval unit escorting several transports - preventing a 2/3 chance of me simultaneously sinking the last remaining enemy naval unit - sneak attacks can be devastating.

Excellent point, Mike. I was hinting at this point in the section quoted below, but didn’t go into specifics:

@Make_It_Round:

We have seen, then, that there can different alternate principles of casualty selection in combat for every attribute a unit has: cost, movement, attack / defense values, and special abilities. Without getting into too detailed a series of explanations, if you require a unit’s ability to ‘blitz’, ‘bombard’, ‘strategic bomb’, ‘torpedo attack’, or even ‘ability to take over enemy territories’ then it may be exempt from every principle of selection mentioned thus far.

Let’s say that you’re attacking an enemy cruiser with a destroyer and a sub. Both miss on the first round, and your opponent hits with her cruiser. It seems fairly obvious that, if you plan on pressing the attack, your destroyer has to be chosen as the first casualty, despite the fact that it is more expensive and is hardier (more pips on the defence), and equal in terms of pips (on the attack) and mobility. This is, of course, due to the sub’s special abilities in this particular combat, namely ‘sneak attack’ and ‘submerge’.

‘Sneak attack’ at 2 is strictly better than a regular attack at 2: the sub gains the advantage here by its potential to pre-emptively reduce the # of enemy pips. We can calculate this value by multiplying the chance of the enemy unit hitting by the chance of success of the ‘sneak attack’. In the case of an enemy cruiser, 3/6 * 2/6 = 1/6 [17%]. So the value of a sneak attack is roughly +1 pip (against a cruiser). Against an enemy battleship, the value of a sneak attack is raised to 22%. Added to the regular attack value of a sub’s 33%, one of your subs vs. a battleship should give you better results, on average, than one of your cruisers vs. a battleship (as long as no enemy destroyers are present), meaning your cruiser ought to be chosen as a casualty before your sub when fighting an enemy battleship.

‘Submerge’, on the other hand, gives a huge boost to your sub’s hardiness–so long as there are no enemy destroyers within range to pick it off during your opponent’s turn–as it can avoid all other forms of combat until you are ready to move it again. So the only principle that could justify the sub as a ‘smarter’ casualty choice in the combat discussed above would be replacibility… but the mere 2 IPC gap in the costs of the destroyer and the sub make this consideration largely irrelevant here. In short, the sub’s special abilities modify our interpretation of the principles and yield the result that it should be chosen last as a casualty in this scenario.

Of course, we could construct many other scenarios wherein a sub would be the first unit we would want to remove from the board…

Part 2 of this series of articles on the Conduct Combat phase can be found here:

http://www.axisandallies.org/forums/index.php?topic=19931.0

One additional point on this subject which I wanted to mention, and which is becoming much more important with the release of Global 40, is multi-power defensive combat.

The four regular casualty selection principles apply to these battles, but there are some additional considerations to bear in mind:

In terms of replaceability, a German fighter and Italian fighter both cost 10 IPCs. However, this is misleading: due to the German player’s much higher income, the German fighter is actually much easier to replace than the Italian fighter. When in doubt as to which power’s units to remove–when the units are of the same strict value–you should simply destroy the unit of the power with the highest income.

[It becomes more complicated when the units have different costs–let’s say a German tank vs. an Italian infantry, in a game wherein Germany is earning 40 IPCs a turn, and Italy earning 10 IPCs a turn. For every 1 unit Italy buys, Germany can buy 4 of the same unit. If keeping Italy strong is a high priority for you, you could value every German unit at 10/40, or 0.25 its usual worth, to reflect the economic disparity between the two powers. This has the undesirable effect of making a German tank ‘more replaceable’ than an Italian infantry… and a German battleship ‘more replaceable’ than an Italian sub. Needless to say, the Italian player would have to be a very good at debating to get the German player to agree to this priority queue in terms of casualty selection.  :wink: ]

In terms of hardiness, and mobility, there are no alterations to the principles. However, with regards to pips, it gets a bit tricky if it looks like you will survive the defence…

If you need a ‘can-opener’ manoeuvre against a minimal enemy force on the next turn, the smaller power has to retain as many of its units as possible, even if that means sacrificing ‘better’ units with higher pips owned by the larger power.

However, if you’re facing a large enemy force in an adjacent territory, the smaller power’s units should be destroyed first, as the larger power will need as many of their units as possible to attack together at the same time on their turn, in order to minimise casualty attrition when they conduct combat.

There is more to said on this subject, I suspect, and I hope that readers will spot any mistakes I’ve made here and will fill in the gaps with their comments.

Hi Ozimek,

I think you’re right that turn order is important, but I think you can also cash out this realization in terms of ‘hardiness’ and ‘mobility’.

This is because what makes the Italian units more valuable in your examples is their power to survive, and/or pose an immediate threat to Allied forces; factors which we can calculate in isolation or in combination on my proposed analysis; whereas mere ‘turn order’, as you describe it, seems to introduce ambiguity by glossing over this distinction.

Additionally, as I argued above, we may have good reason to think of Italian units as always a better choice for preservation than their German counterparts, due to their relatively weak ‘replaceability’ factor.

Best,

M_I_R