Editing Warhammer 40,000/7th Edition Tactics/Psychic 101 (section)

== 2: Casting Powers ==

Okay, so you have a bunch of dice waiting to be turned into mindbullets or whatever. Next up, ''using'' them.

The player actively casting powers (you, in this exercise) chooses one of his psykers and one of the powers that psyker knows; if the power has a variable cost, choose the cost now. You then choose a number of dice from your psychic pool and roll them. Every roll of a 4+ on a psychic dice is an activated 'warp charge'. Each power requires a certain number of warp charges to go off - most take one, a handful need two, and a few rare ones take three. If you got enough warp charges from your psychic dice to meet or exceed the number of warp charges for the power, the power activated successfully. If you failed to meet the number of warp charges on the power, it fizzled - the dice used in casting it are wasted, and the power doesn't go off.

'''Notes:'''
*Casting psychic powers no longer affects the rest of the psyker's actions on the turn; a psyker can cast any of the powers he knows regardless of whether or not he moved on his Movement Phase, and casting psychic powers does not prevent him from running, shooting, or declaring a charge on the following Shooting and Assault phases. Being locked in combat does not prevent the psyker from generating dice, but does prevent the psyker from casting Witchfire and Focused Witchfire (shooting attack) powers. Buffs, debuffs and summons are A-OK though.
*A psyker may cast multiple different witchfire (shooting attack) powers during your psychic phase, as long as he has the necessary dice, may target them at the same or different units as he pleases, and unlike with regular shooting attacks, is not limited to charging at one of those targeted units in his assault phase.
*Psychic dice are not 'earmarked' for the psyker who generated them; it's entirely possible for you to use all your psychic die to manifest dice from one of your psykers, regardless of where the dice actually came from.
*A psyker in a building or a transport can manifest ONLY witchfire and focused witchfire (shooty) psychic powers, and even then only if he can draw line of sight to his target from the transport's/building's fire points or the transport itself (if open-topped). If your psyker intends to cast buffs/debuffs or anything more elaborate than blowing shit up with his brain, he's got to climb out of that metal box first. Similarly, units that are inside a transport or building cannot be targeted by a psychic power, beneficial or not. (The battlements of a building are not considered to be 'inside' a building, so a psyker can stand, say, on the roof of a Bastion or on a Skyshield Landing Pad and gain a degree of protection from that).
*Any one psyker can only attempt to manifest a given power once in a psychic phase, regardless of if it failed or succeeded. Two psykers knowing the same power can of course each (attempt to) cast it, at different or same targets.
*A single unit can only be affected by one copy of a given blessing at any one time - so Hammerhand, for example, no longer stacks. Two DIFFERENT blessings on the same unit are A-OK, though.
*Since psychic powers are used in the Psychic phase, you cannot use a witchfire power to shoot Overwatch if you get assaulted.
*Any dice not used in casting powers are lost and wasted at the end of the psychic phase.

=== Warp Charge Table===
The following table shows what chance you can expect to cast a power for a given number of warp charges. Note that this for the standard odds of harnessing (4+) and periling (at least 2 sixes), and hence does not cover situations where harnessing is improved or periling is more likely (such as with Daemonology).

{| border=1 cellspacing=0 cellpadding=4 align=left style="text-align:center;"
|+ Chances of Success and Perils for Charges and Dice
|- valign=top
! Dice !! Success, WC1 !! Success, No Perils, WC1 !! Success, WC2 !! Success, No Perils, WC2 !! Success, WC3 !! Success, No Perils, WC3 !! Perils
|-
| 1D6 || 50.00% || 50.00% || 00.00% || 00.00% || 00.00% || 00.00% || 00.00%
|-
| 2D6 || 75.00% || 72.22% || 25.00% || 22.22% || 00.00% || 00.00% || 02.78%
|-
| 3D6 || 87.50% || 80.09% || 50.00% || 42.59% || 12.50% || 09.26% || 07.41%
|-
| 4D6 || 93.75% || 80.56% || 68.75% || 55.56% || 31.25% || 22.22% || 13.19%
|-
| 5D6 || 96.88% || 77.25% || 81.25% || 61.63% || 50.00% || 33.85% || 19.62%
|-
| 6D6 || 98.44% || 72.12% || 89.06% || 62.74% || 65.63% || 41.91% || 26.32%
|-
| 7D6 || 99.22% || 66.20% || 93.75% || 60.73% || 77.34% || 46.15% || 33.02%
|-
| 8D6 || 99.61% || 60.08% || 96.48% || 56.95% || 85.55% || 47.23% || 39.53%
|-
| 9D6 || 99.80% || 54.07% || 98.05% || 52.31% || 91.02% || 46.06% || 45.73%
|-
| 10D6 || 99.90% || 48.35% || 98.93% || 47.38% || 94.53% || 43.47% || 51.55%
|}<br style="clear: both; height: 0px;" /><br>

Generally, for a good chance of success you need to use double the warp charges of the spell's level to beat a pure coin flip; you can add 1 or 2 charges, with diminishing returns, to increase your odds, but should never commit more than 2 extra charges, as your odds of perils will become too high to be worth it.