One thing I've generally noticed with
40k tactics articles/discussions, is that a lot of them focus on the list-building aspects, but "how" to use the armies in-game seldom gets discussed. So this thread is more about "how" you play your army in-game, and "general-purpose tactics." I'm dumping some stuff I contributed to an older discussion on Reddit about it, and seeing if there are other things that can be added/expanded upon.
==Regarding Vehicle Movement==
-One of the biggest tips is to make sure the rules for vehicle movement are strictly followed. Vehicles move forwards, backwards, or they pivot on the spot: In The Grim Darkness of the 41st Millennium, there is No Tokyo Drift. Likewise, you should strictly enforce the 1" rule.
-What this means is that if you park your Rhino 1" to the side of your opponent's Rhino, both Rhinos get locked going in one direction, until they can move far enough that they can turn without coming within 1" of each other.
-If you have enough light vehicles, it makes sense to run them in semi-linear convoys for several reasons: Optimizing your cover while minimizing that of the enemy, providing screening, and supporting through crowd control. ("Fish of Fury" is the oldest example, but Sisters and Marines do the same thing with Rhinos)
-Remember that you trace line-of-sight from the weapons of your vehicle to the hull of their vehicle. For vehicles with elevated weapon turrets, what this means is that if one vehicle "takes point" in a convoy/train formation, it can grant cover to the vehicles behind it, while the enemy does not necessarily benefit from cover against shots taken by your vehicles' weapons.
-Tank Shock is not so much for forcing morale checks (though Everything Counts In Large Amounts), as much as it is for crowd control. Remember that Tank Shock has a strict order of operations. You don't displace enemy models until you place your vehicle on its final spot, and then those models have to be displaced the closest possible distance away. What this means is that judicious use of tank shocks can force enemy models into crowded "Please Flame Me" formations, or you can use it to minimize the number of models that can Overwatch or Pile In to an assault you launch.
-Note that in most games, anti-tank is about multiple medium-strength shots scrubbing off Hull Points, rather than smaller high-strength shots hoping to explode them. In the case of the Rhino, (or any other vehicle that has access points on its sides), you want to advance your vehicles at a rough diagonal to your opponent's heavy weapons fire, so that should you lose your transports, the models can disembark on the side hatch (rather than the rear) away from follow-up attacks. If you run your vehicles in a semi-linear formation, even if multiple vehicles get destroyed in one go, you can have the advantage of an impromptu defensive barricade, one which ideally has been set up in the center of the board to control or at least threaten multiple objectives.
==Regarding Combat==
-Generally speaking, don't rely on blast or flamer weapons to rack up large numbers of kills, as an enemy general can easily spread out his models to minimize the damage done from such powers. More than anything, they exist to keep the enemy honest, or prevent an extreme concentration of power. That said, there are three major ways for units to end up inadvertently grouped-up:
- When the unit is displaced from one or more Tank Shocks.
- When the unit rolls low to consolidate after an assault (of note is the fact that models cannot consolidate after assaulting a vehicle). Don't forget your flamers for the second wave.
- When the unit loses its transport, either to a wreck or explosion. A classic "one-two-punch" for a Marine army is to use heavier weapons to destroy enemy transports, then immediately follow-up with the Thunderfire cannons before the surviving passengers can spread out!
-If you want to maximize the amount of damage done to bunched-up models, four AOE weapons firing from the same unit will inflict more damage, than from four different units. To use a vacuum example, let us suppose you have a unit of Chaos Chosen with Four Flamers, as opposed to four units of Chaos Marines, each with a Flamer, and they're alternatively firing at a unit of Orks.
- One unit fires four Flamers at the unit of Orks. Each one hits 5 Orks, for a total of 20 hits. Then you roll to wound/remove casualties.
- One unit fires a Flamer and hits 5 orks. You roll to wound, kill about 2-3 Orks. The next unit fires a Flamer, and hits 2-3 Orks, killing 1-2 of them. And so on so forth.
-Many squads gain a disproportionate amount of strength from any special/heavy weapons they are carrying with them, or from the occasional superior character leading said unit. As a result, there are some occasions where you can mostly neuter the strength of the unit if you kill those specific models. Although Characters can get "Look Out Sir" rolls, troopers armed with upgraded weapons do not. Thus, they tend to hide in the "Center" of a formation, where they are shielded by their buddies (since the closest models from an attack vector are hit first).
-There are two main ways to single out enemy models in a unit: The first is to use weapons which can single out specific models. This includes attacks with the Precision Shot rule, or Beams/Focused Witchfires. This method usually suffers from inefficiency (Focused Witchfires, in particular, are exceedingly
WC-intensive for their effect). The second way is to force key models to be the the closest visible ones singled out by your firepower. Several options for attaining this include:
- Using "Barrage" weapons (Mortars/etc) changes the attack point of origin from the firing unit's location, to ground-zero of the blasts in question.
- Another way is to carefully track "Order" of operations and go "Which models will do the most damage if they fire first". Because you must declare the order-of-operations for weapons fired by your unit, you could easily do something like: "Fire the flamers first to hit the maximum number of chaff models, fire all Bolters to clear out remaining rank-and-file models of the unit, then my plasmagunner on the right flank of my squad so that the closest enemy model he's shooting is their plasmagunner."
- Make multiple attacks from the same area: If you can "Move And Fire" (Battle Focus, Onslaught, Hunter Cadre Feints & Ambushes, etc), you can have one unit fire, then have the next unit move just enough that you can dictate which enemy models in the target unit are "closest."
- Blocking off visibility to the parts of the enemy unit you don't want to shoot is the most reliable way, though it comes with the risk of losing excess firepower. This is yet another reason why Rhinos and convoy formations can be nasty. You can play "Space Invaders/shooting gallery" with your troops forming a triangle, and firing at a distinct subset of models they wish to remove.
==Assault==
-As a general rule of thumb, you want to break or destroy your enemy in your opponent's assault phase. That way, your opponent does not have a shooting phase before your assault teams move towards their next target.
-Generally speaking, Overwatch is more of an annoyance than a true threat, though certain rules, bonuses, etc (Dark Angel Chapter Tactics, Tau Supporting Fire/Counterfire Defensive Systems, Cognis Flamers, D-Scythes, etc) can take a nasty toll, especially if you're relying on glass cannon units (Harlequins notably). Some special "Negate Overwatch" powers exist, but there are other ways to mitigate the effects of Overwatch.
- Pinned units cannot Overwatch. However, this generally is not a state you can reliably inflict on your opponent.
- Overwatch takes place before you move your charging unit, and is still subject to normal rules for Line of Sight, cover, etc. Moving a Rhino or other vehicle flat-out to block off models from shooting your chargers is always a valid trick.
- If blocking Line of Sight is not an option, then aim to eat the overwatch. One way to do this is to have a "tanky" unit lead the vanguard. For example, when charging a unit armed with multiple flamers, have a fast monster/walker lead the charge.
- Alternately, there's sacrificing an otherwise-depleted unit. If you have one grunt remaining from a squad, have him charge first before following up with a more intact unit. Either your opponent must waste the Overwatch killing that one single model, or risk that model tying up up the enemy unit and preventing the Overwatch anyway.
-Remember that pile-ins use the same overall rules for charging, and thus any unit must ultimately maintain coherency. When attacking a large spread-out unit, you can negate a lot of its strength by attacking on opposing flanks.
-Multi-assaults are where things get interesting. Remember that (challenges notwithstanding) should a model be engaged in an assault with two enemy units, and is in only base-to-base with models from one of those units, it must allocate its attacks against that unit. What this rule means, is that if you have more valuable units you wish to preserve in assault, then you can plan your attack vectors accordingly. Hilarity is forcing Commander Smashfucker to waste his Strength 10 super-hammer of doom on rank-and-file Termagants while his bodyguard is being eaten alive by the nearby Carnifex!
-The ability to quit close combats is a very powerful ability. It can be defensive, preventing ranged units from being tied down in melee, or it can be offensive, allowing assault units to "pinball" around the battlefield. Hit & Run is the main evasion ability, though Gate of Infinity finds its use as well (attaching Draigo to a unit of Centurions is the classic one-two of the infamous "Gravstar"). Another dirty trick you can use Hit and Run for in conjunction with a sufficiently durable unit (ex: A Conclave of the Burning One with a Deceiver Shard) is "Pulling" units off objectives. Attack the unit from the flank, wait for them to consolidate away from the objective, Hit & Run, and repeat the process.
