Wednesday, October 31, 2012

Overwatch!

I've been thinking about overwatch a lot, lately, and specifically trying to think of ways to get around it. After all, I don't like my wyches getting shot at the best of times... I suppose running in to assault is the best of times, and I certainly don't like being shot then. So no. I do not like my wyches being shot, ever :)

But what to do? Unfortunately I haven't had the chance to play a lot of 6th ed yet - precisely one game. So what follows is a brainstorm of sorts, of untested ideas to get the girls engaged without getting gimped.

Take it

The easiest route is just to take the damn overwatch, and dare it to do any significant damage. Fine if you're an incubus, grotesque or wrack. Not so fine if you're a wych or a hellion.

Pain tokens will of course help out against a lot of overwatch fire. But will they help enough?

Say I manoeuvre some nine wyches into combat against a full, standard tac squad, complete with missile launcher and flamer. In the assault, I'd have a 64% chance of winning the first round outright, although the odds of winning the protracted combat aren't so crash hot. Anyway, if for whatever strategic reason I want to give it a run, how does overwatch affect me?

1 bolt pistol shot, 14 bolter shots, 1 krak missile shot and d3 flamer hits. The bolt rounds average 2.5 hits, 1.66 wounds. The krak missile averages 0.14 of a wound. The flamer averages 2 hits, 1.33 wounds. So on average 3.14 wounds.

A pain token would mitigate this slightly, though it could do nothing against the krak missile; leaving the average at 2.14 dead wyches. Of course I can only fit nine in the raider if I stick a haemy there. And with two less, my first round odds have dropped from 64% to 57% chance of winning; my chance to win the combat as a whole has probably dropped more precipitously.

Curiously, leaving the tenth wych at home to insert an haemonculus equilibrates to seven wyches hitting this enemy, the same as ten wyches without feel no pain charging.

Is there a better way?

Take cover from it

Assaulting from cover gives you a cover save, which will generally be a 5+ or perhaps a 4+ if you've equipped a phantasm. In the aforementioned scenario a 5+ cover save reduces the wounds from bolters and the missile from 1.8 to 1.2; a 4+ save reduces the average to 0.9. However the flamer still inflicts an average 1.33 wounds, resulting in 2.53 and 2.23 wounds getting through the cover, respectively.

A pain token reduces this to 1.72 for a 5+ save, or 1.51 with a 4+ cover save. If you can somehow arrange to be assaulting with your phantasm hekatrix-led wyches from behind an aegis or other hard cover for the 3+ save, you are a master of battlefield positioning, and should suffer only 1.93 wounds, or 1.31 wounds with feel no pain.

At this stage it should be clear that a pain token is generally a better investment than cover by itself, but equally there is no reason not to try and get both. Particularly since flamers ignore cover, and S6+ ignores feel no pain... the more saves, the merrier.

Assaulting through cover has its drawbacks, the most salient of which is the reduced movement. The average assault distance for a fleet unit through cover is 8.1", compared to 9.5" in open terrain. If you are running a phantasm this isn't really  a huge concern, since you will want to be within 8" anyway, but be mindful that you will have 10 - 20% extra chance of missing the assault. And then overwatch casualties were all for nothing!

Luckily wyches come with assault grenades, so striking last is not a problem.

Block it

An easy trick for any imperial army seeking to limit the effect of overwatch on its dudesmen is to park a metal box in front of the majority of the enemy unit, leaving only a thin corridor for the chargers to navigate, but blocking line of sight and hence overwatch fire from the majority of the enemy.

That would be fantastically useful for a Dark Eldar army, particularly given the utility provided by an 18" flat out move.  Unfortunately, all of our vehicles are rather inconsiderately hovering some distance above the ground. Not only that, but they are rather less box-like than their humie counterparts - not that that is necessarily a bad thing, but it does mean we have to think a bit harder to achieve line of sight blockage.

Really, we need to achieve this by wedging our enemies against terrain that blocks line of sight, which potentially also provides cover for the models that can be seen, while probably reducing the assault distance as discussed previously.

You could of course model your skimmers on very short bases or trailing large sheets beneath them to cover up the enemy. You may experience some unwanted side effects though, like people refusing to play you again :P

Allies are another option - just bring in some guard or marine allies to get cheap and plentiful metal boxes. However, placing these near your assault units, which is where they will ultimately want to be, is likely to force 'one eye open' checks, which in turn can screw your assault a lot harder than overwatch.

Also note that arc of fire is relevant to walkers that want to overwatch. If you can assault a dreadnought from behind, it won't get to fry you with its heavy flamers.

Tank it

What to do when all else fails? Send in another unit to take the pain.

Units can only fire overwatch once per phase. Furthermore, once engaged they cannot fire at all. As charges are resolved sequentially, if a first unit succeeds in assaulting, or at least drawing overwatch fire from a target, a second unit can charge scot free.

Therefore, charge your target with something else before sending in the wyches.

Two categories of candidate units spring to mind: resilient units, and disposable units.

A resilient unit might be a talos, some incubi with a pain token, or some grotesques or something similar, something that can take the hits and probably keep coming. Reavers, with T 4 and 4+ cover save that they bring with them are worth a nod if there are no flamers around. A Donorian clawed fiend is particularly hilarious, since any wounds it does suffer from overwatch make it even more ferocious once it hits combat.

On the other end of the spectrum are units that you just don't care about. A single beastmaster with two khymerae will run you 36 points, and with 12" moves that ignore cover stand a good chance of being where you need them to be. A 4+ invulnerable gives them half a chance of surviving to reach the combat, and if they survive that the last one can repeat the trick next turn.

This can be tricky to do in 2 missions however, as the unit will give up a victory point in the Scouring, and also Purge the Alien. Neither case is optimal, and a 1/3 chance of not being so disposable bears some consideration. As a silver lining, in the Scouring you gain a very cheap scoring unit that can take a far-flung objective away from the main battle. Alternatively, consider 3 Mandrakes, who will only give up points in Purge, although they are not particularly fast; but to some extent infiltrate can ameliorate their lack of (super) speed.

You can also make some units mid-way between a resilient and a disposable unit. Reavers can be this, and a small squad of 5 scourges can do the job as well. Shardcarbines soften the target first, 4+ armour helps them tank overwatch, and the wyches then come in to do the dirty work. A pity scourges can't take haywire grenades, or they could do double duty with just the basic loadout.

Beat it

That brings me to the other, perhaps more obvious way of mitigating overwatch: killing half of the target before you assault.

Frankly, Dark Eldar should be doing this anyway. Any squad will have a much easier time killing 5 space marines than 10. Losing fewer wyches to overwatch will be repaid doubly by losing fewer in assault, too.

And unlike some other options, we natively have plenty of tools to thin out their numbers by shooting. Razorwings, venoms and disintegrator ravagers get an honourable mention here.

Integrate it

Ideally the cunning Archon will have access to a little bit of everything listed here to make their assaults progress as smoothly as possible.

There's my theory hammer. Any other ideas? I hope to get the chance to test some of these in action soon, in the meantime let me know if you have experienced any particular success in the best of times, aka the Assault phase :)

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