Editing Warhammer 40,000/9th Edition Tactics/Space Marines (section)

===Army Building===
====Army Composition====
Balance cool minis and Your Dudes with an answer to "how do I kill Russes, termies and gaunts?". Especially, how do you plan on killing those dudes wielding marine-killing D2/D1d3 weapons. Answer these questions first, ''then'' you can begin thinking about what you want to bring to the table.

Deciding on what units to take generally comes down to what you want your force to accomplish on the tabletop. One school of thought is to avoid having too many various “types” of marines in one force, instead focusing on using lots of similar profiles in order to force opponents to attack units using suboptimal weapons. Using very little vehicles and lots of Infantry “wastes” your opponents anti-tank shots, for example. Or by having lots of heavy infantry and armour means that the small arms fire directed at you will be less effective (Marines have non-heavy infantry?). Other schools emphasize the modular nature of Space Marines and prioritize the taking of multiple styles of Marine units in order to more effectively deal with various threats. These two schools are extremes, and good list building most likely lands somewhere in the middle.

The goal of making an army themed around a specific profile type is to reduce the effectiveness of your opponents shooting- an all-infantry army being more effective against anti-tank weapons is an obvious example, but similar principles apply to things like multi-wound attacks being overkill against single-wound units. However, this idea has one catastrophic flaw which should always be kept in mind: when the opponent is able to counter your chosen style and you don't have any units not of that style, they will counter you '''''hard'''''. Try to figure out what your enemy will be likely to use ahead of time so you don't pay for putting all your eggs in one basket!

The T5 family is all bikes (Scout bikes, Attack Bikes, Outriders, Invaders, standard bikes), and Gravis units (Heavy Intercessors, Eradicators, Inceptors and Aggressors). They'll be able to take a beating and things like Pedro Kantor+Aggressors are a powerful combo, but Bikes and Gravis-armoured Primaris Marines don't synergize very well with each other and you might end up leaving half your army behind if you don't pay extra for Repulsors (and it has to be Repulsors, Impulsors don't carry Gravis-armoured units).

Finally, think about your own play styles and how you prefer to command an army. It is important to determine before hand how you intend to play the game and generate an army fittingly. Marines have by far the most expansive and complex codex which means we have units for every situation. Once you master yourself you must master the codex, as again, Marines have an incredibly diverse and complex ruleset, and you need to understand each action you can take in each stage of the game. After you have done these two steps, you can finally chose a Chapter Tactic. Marines can march right into close combat, kite enemies in mid range gunfights, and hold firm at range with powerful heavy weaponry all equally well.

=====Picking your chapter=====
	
As there as so main chapters there is a section going over which ones are better at what things. Many chapters can do similar things and get the same buffs on a single unit but the true difference is which chapter abilities are individual, Auras, or army-wide.
 	
*'''Ultramarines:''' Lends itself as a Jack-of-trades army, being decent both shooting and fighting. Pure Ultramarines does lend itself more to a moving gunline list, ignoring penalties for moving and falling back, and some improved shooting stratagems,  along with some Heroic intervention, mass Overwatch, and CQC characters and abilities. Think of it as a T'au/Kroot list that wouldn't fall apart if they got into melee as we are dealing with marines bodies instead of those pansy Blueberries. They have slightly better control over combat doctrines with a preference for the Tactical doctrine, with heavy weapons also benefiting along with Eradicators, and several Forge world tanks gaining extra shots despite moving. A single detachment of Ultramarines or one of their successors can support many builds with a mix of different units.	
**'''Silver Templars:''' They take all the melee tools the Ultramarines have and double down on it. They also have a propensity for taking big power weapon on sergeants as they had the per nerfed Salamander rerolls for melee attacks. Being Ultramarines successors, they want to make a melee-focused army but they also still get all the Shooting tricks from your parent chapter, so no reason not to also have big weapons. 
**'''Emperor's Spears:''' These guys blend the tactical decisions of Ultramarines with the melee potential of the Blood Angels. Power weapons on your sergeants are a must. Similar to the Silver Templar in that they get the shooting tricks of the Ultramarines but are definitely a melee focused army. They are better at closing the gap than Silver Templars, however, and with Redden the Earth stratagem the wound a lot easier.
*'''Iron Hands:''' Has an affinity with Vehicles, durability, and some bonus to attack roll in melee and shooting. Iron Hands are the chapter that keeps their vehicles operating at max capacity for a long time, even giving back the shooting bonus that was enjoyed before the 9th codex. In addition, Iron Hands are well suited for protecting their characters, Dreadnoughts, and come with some extra Deny the Witches. Whether it's from vehicles or infantry attacking stratagems for improved firing and chainsword lines.
*'''Imperial Fists:''' You're a Siege tactics army, Wanting to sit back behind a fortified position and drawn the enemy in bolter rounds while destroying all Building, Vehicles, and Cover they could hide behind. Fists are about taking a lot of bolter welding units like Heavy bolters and hurricane bolters on vehicles. 	
**'''Crimson Fists:''' Similar in many ways to their yellow brothers, the Crimson Fists shine when facing overwhelming hordes and have various options for rock hard characters. 
*'''Raven Guard:''' Smooth operators, the Raven guard are a shooty army that possesses complex maneuverability for vicious one-two punch tactics. These guys also take advantage of the Tactical doctrine and have a habit of "incapacitating" characters/HQs. Not a novice chapter like the Ultras. While they gain bonuses at range, they have potent assault options as well that can advance and charge. 
*'''Salamanders:''' The Salamanders utilize tough infantry and higher quality ranged weapons. Being masters of flamers and meltaguns, they favor short ranged gunfights and take advantage of powerful, single shot guns as well. The Salamanders also have some pretty heavy duty HQs and don't mind some buffed vehicles as well. 
*'''Deathwatch:''' Being Inquisitorial based, Xenos slaying special forces Marines, this is a highly tailor fit army. Naturally they can really bring the hurt on anything without CHAOS or IMPERIUM keywords, though these guys require some patience and practice. Their Infantry units offer potent short ranged dakka and are highly customizable, though you will find they can become quite expensive. Deathwatch armies are all about positioning the right unit in the right spot, as its best to focus each unit on a specific task, rather than making bigger multi-purpose squads. Vehicle wise they are fairly vanilla, while they have the most diverse troops section in the game.
*'''White Scars:''' has a need for speed, with most of their ability focusing on movement, ignoring the downsides of advancing, getting into combat quickly. White Scars are about covering as much ground as you can and then start cycle charging. Although there is an emphasis on bikes, it also works with jump packs and transports. Most Bike units should be able to reach enemies by at least turn 2, but after that, all melee weapons can have 2 damage which works out for when engaging Vehicles and MEU. 
*'''Blood Angels:''' The bloody golden Marines, Blood Angels are a melee first army. Sporting very swift and very high output Characters alongside elite Infantry; they are a fast paced army, hard hitting army. They are offer a lot on the offense, though they can be countered rather easily and don't always absorb as much damage as they deal. Blood Angels players need to balance carving your opponent into little pieces with actually playing the mission and securing objectives. Take advantage of the fact that your opponent expects Death Company and Sanguinary Guard to rampage all over the board, though they will probably ignore your mid/back field campers... Or go full tilt and max out on Death Company and Sanguinary Guard, It will be awesome win or loose. 
*'''Dark Angels:''' Can be used to easily crush enemies any which way with your 3 doctrines for the different wings. Their “main” doctrine loves heavy weapons and plasma especially, having doctrines to pulverize opponents into fine meal. The Ravenwing and Deathwing both open up extremely durable tools to complete any job you want, and a Ravenwing Chief Apothecary is nearly mandatory if you bring some of the best bikes in the game. Units can get expensive, but there is little Deathwing Knights cant smash or Ravenwing Knights cant chase down. 
*'''Space Wolves:''' Similar to the Blood Angels, the Space Wolves prefer to destroy their enemies in brutal hand to hand combat. Perhaps the most codex divergent of all Space Marine Chapters; the Space Wolves have powerful characters and some impressive melee units, while their ranged game and vehicles are typically no better or worse than others. Space Wolves armies can be found with either a small number of high output units including upgraded dreadnoughts, or running larger numbers of infantry. Space Wolves can also be fast when needed, something to note when slaying your foe. 
*'''Black Templars:''' The Black Templars are a very thematic army that doesn't really diverge too much from the main Astartes codex. They don't have any librarians, yet they resist mortal wounds on a 5+ and they can re-roll charges. They usually find themselves taking advantage of aggressively deployed and/or vehicle borne infantry fighting at close range followed by a righteous melee (AKA ruthless slaughter).

====Bringing Allies====
In general, you use allies to cover your weaknesses, such as the marine's usual lack of hordes or particularly heavy vehicles by bringing in guard, skitarii, or knights, but be aware that you will sacrifice the HUGE benefits of Combat Doctrines unless the other detachments are also drawn from Codex: Space Marines- and even if they are, you'll lose your Chapter-specific Combat Doctrine boost if its Chapter Tactics are different. Adding this to not only the CP cost of taking an allied detachment but also the sheer variety of options you have as the posterboys, there's almost no reason to bring anything other than an inquisitor (with their risk-free, no downside but costly ways of being brought) in your marine list.

=====Specific Mixes=====
Specific combinations are mainly dependent on your chapter trait but there are some combo's that are great for any army some examples are shown below:

*Grav-Bomb, stick some grav-cannon devastators or grav-centurions in a razorback, stormraven or rhino with a captain. Yeet it up the board ideally keeping out of LOS or at least partially obscured, then drop off your devastators or centurions in cover somewhere just in range of a nasty enemy unit ideally a centrepiece unit with a high armour save (at least 3+). Then drop the 1cp  stratagem to re-roll all wounds and damage rolls for the unit and if your using devastators use the armorium cherub too. That's 4 shots each at strength 5 AP -3, hitting on 3+ rerolling 1's and re-rolling all wounds and damage rolls. Usually this is enough to make targeting your devastators a priority for your opponent and in all likelihood they're going to take heavy casualties but the unit will have easily made back its points by then and seriously disrupted your opponents army.
**If you're Iron hands or a successor then you can move these guys without any penalty to hit and re-roll 1's without a captain so that's something to consider, only works in the devastator doctrine though.
**Effective against hordes as well so this combo is still good against swarm lists and those army's will have a hard time dislodging your guy's from a ruin. 
*Captain and hellblasters, pretty self explanatory stick a bare bones captain near a 10 man squad of hellblasters and fire on overcharged with only a 1 in 36 chance of dying each time you fire, generally works best if you use a impulsor as this allows you to move a fair distance BEFORE DISEMBARKING to shoot with no penalty to hit, if you're within 15" then that's 20 shots at s8 AP-4 which is enough to cripple or kill almost anything without an invulnerable save.
**Although this unit is a serious threat to your opponent it's unlikely to be killed off early, an impulsor's fairly tough anyway if you give it the shield dome equipment and hide it behind a wall it becomes incredibly difficult to remove turn 1. Not to mention that if you have the right threat saturation in your army then your opponent is unlikely to shoot this thing anyway.
*Aggressor auspex scan, when playing against an opponent like daemons, orks or tyranids it's pretty common to have a swarm of infantry pop up to charge you out of deepstrike, ordinarily this can be a real problem as many of the units available to these armies have ways of getting a very easy charge. This trick's for just such a situation. When you deploy your units leave a nice gap behind your lines where an enemy infantry unit could deepstrike just in range of your agressors ideally a unit of six that hasn't moved, when your opponent tries to deepstrike his infantry play the 1CP stratagem to shoot all your aggressors at his guys TWICE at a -1 penalty, (you should have a chapter master in range anyway so that's not too big a deal) even with a 5 man aggressor unit you should annihilate any light infantry that tries to deepstrike for just 1 cp.
**With iron hands chapter tactic then you can pretty much get the same effect on normal overwatch, for 1CP you overwatch on a 4+, 75% accuracy near a chapter master.
* Gravis Bombs (all types). Can be done with any chapter really, even Forge World offshoots and codex deviants like BA, DA, SW, and DW. Take 6-10 Gravis models of any variety along with an apothecary and an ancient. Find some way of providing a FNP or Invulnerable save and plant them in cover. Makes for an extremely durable T5, 18-30 wound unit that can shoot/fight whenever it loses models and can regain slain models. Finally, it creates a roughly 3' ''dead zone'' on the board, as enemy units that get near it will be zapped with anywhere from 20-36 S4 or S5 bolter shots, potentially even double plasma or flamers. Finally, you can take another two squads for another 36-60 T5 wounds. Finally all of the Aggressors come with 3 attacks base and powerfists... 
** Three squads of Heavy Intercessors for god damn 90 T5 wounds can be done for 840 points. That's tougher than like ~30 Dark Eldar little fighter planes and packing 90 Attacks on the charge and up to 90 S5 shots, or 30 S5 AP-2 D2 shots, all with obsec.

====Character Buffing====
For those of us that want a pure marine army it is important to double up on your force multipliers at every opportunity. The Troop Tax is no more; it is replaced with the HQ tax. Use your HQs to their maximum. And while HQs and the Lord of War Guilliman improve your hitting and wounding, units inside the elite slot have created a new dynamic for Marines. The Marine Formula -- a Unit and it's accompanying support Unit, goes for all the non-character models. 
*Ancients are must-takes in infantry-heavy Space Marine armies. Ancients enable out of turn shooting from models you'd otherwise be removing from play, even on your opponent's turn and help reduce the toll of Alpha Strikes: getting shot off the board Turn 1 is a thing, and Ancients help you recoup some of your losses by returning fire as models die.
*Apothecaries. Make him Chief and give chief's warlord trait, and you'll get auto-reviving machine, who is also heals twice and supplies FnP on 6's. Best with heavy cessors, aggressors, bladeguard vets and other elite infantry.
*Build around your Warlord! HQs like Kantor, Shrike, Vulkan, and Khan can drastically change your army's peak efficiency. Using Vulkan around loads of Melta toting marines is more efficient than Kantor around the same loadout. Conversely, Kantor with dedicated heavy assault troops (Assault Centurions, Assault Terminators with Thunder Hammers, Vanguard Veterans with Thunder Hammers, etc.) can take out a Knight in one turn of CC. Without Kantor, they only accomplish 50% of the damage. 
*Another popular combination is a Captain (ideally upgraded to Chapter Master if you can spare the points) and Lieutenant; the Captain allows hit re-rolls of 1 while the Lieutenant allows wound re-rolls of 1. Hellblasters and Devastators in particular really benefit from being inside these auras. Chapter Masters and Lieutenants are essential for getting accurate firepower; other armies lack accuracy but make up for it with volume of fire. Marines will usually have a low model count and so need each shot to work.

====Sergeant Equipment====
Most of your regular Infantry and Bikers have a Sergeant that takes items from the Sergeant Equipment List.  This includes your Tactical/Scout/Assault/Devastator Squads, your Company/Vanguard/Sternguard Veterans, and your Bike Squads and Company Veterans on Bikes.  If you don't have specific wargear in mind, '''ALWAYS''' take a Storm Bolter and Chainsword instead of leaving them with their default options.  This 2-point upgrade adds the same amount of dakka as an entire 13-point Tactical Marine/11-point Scout.
*Veteran Sergeants all have 3 attacks, so investing in a nice melee weapon is often worth the points, even if you don't intend to use them in assaults.  A 20-point Thunder Hammer presents a very serious threat to pretty much any multi-wound model, be it Infantry, Monster, or Vehicle.  Taking a Thunder Hammer in this instance is as much about limiting your opponent's options as it is about directly inflicting losses, though landing even a single blow will more than make your points back if you pick the right target (putting it on an Intercessor Sarge helps here since they get one more attack than the other types).
**Saying that, remember that most power weapons are only 5 points. So when low on points left, consider a Power Sword or something like that to cut through armour if you find yourself in combat.