Wednesday, 23 September 2015

Necron Decurion Math-hammer 2 - Wraiths with Resurrection Protocols

Wraiths are hard to kill already, with 2 wounds, toughness 5 and a 3+ invulnerable save. It takes a lot to kill them in their standard state. What happens though when you have them in a Canoptek formation in a Decurion detachment. Madness, thats what happens. Here is the maths behind killing wraiths when they have a 3+inv save and 4+ RP.

Shooting the wraiths with Bolters from Marines

2/3 shots will hit due to BS of 4
1/3 hits will wound due to T5 vs S4. So 1/3 of 2/3 is 2/9 of shots will wound.
1/3 of wounds will fail their save. So 1/3 if 2/9 is 2/27 will fail their save.
1/2 of failed saves will fail their RP roll of 4+. So 1/2 of 2/27 is 1/27.
It will take 27 bolter shots to do 1 wound to a wraith!
To kill a full squad of 6 wraiths, it will take 162 bolter shots. Broken much??

Shooting the wraiths with Krak missiles from Marines

2/3 shots will hit due to BS of 4
5/6 shots will wound due to S8 vs T5. 5/6 of 2/3 will be 5/9 shots will wound.
1/3 of wounds will fail save of 3++. 1/3 of 5/9 is 5/27 shots will fail save.
1/2 of failed saves will fail their RP roll of 4+. 1/2 of 5/27 is 5/54 of shots will actually cause a wound.
It will take 10.8 Krak missiles to cause 1 wound on a wraith! 
To kill a full squad of 6 wraiths, it will take 64.8 Krak missiles.

Killing wraiths with S10 hits (for Instant Death bonus)

I won't start with a BS skill here due to S10 being rare and a variety of different BS of its users.
5/6 hits will wound due to S10 vs T5
1/3 of wounds will fail save due to 3++. So 1/3 of 5/6 is 5/18 of hits will fail save.
2/3 of saves will fail RP due to -1 to RP rolls because of instant death. 2/3 of 5/18 is 5/27.
It will take 5.4 S10 HITS to KILL a wraith.
To kill a full squad of 6 wraiths it will take 32.4 S10 hits. Remember these are hits not shots, you have to factor in BS skill and/or blast scatter first. With a guards man BS of 3 you will need to multiply this by 2 to account for only 50% of his shots hitting.

So basically wraiths are nearly impossible to kill by simply shooting them with guns. They do however have a big weakness. This formation requires a single Canoptek Spyder (Tomb Spyder in old money) to give the formation RP rolls and it needs to be within 12". Either kill the spyder or somehow force the the wraiths away from the spyder. The spyder has to be by itself, not a squad of 2 or 3 spyders, so it is quite vulnerable but it will also have RP too, so T6 with a 3+ save and 4+ RP rolls will also be quite hard to kill. And don't forget the scarabs in the formation will also have 4+ RP rolls, which is just funny.

Necrons as a whole seem stupidly resilient with the Decurion, but seeing things with a 2++ re-rollable save I don't feel too bad about this. While our army is hard to kill, we don't put out that much damage and this (sort of ) balances things out a bit.

Monday, 21 September 2015

Some quick(ish) math-hammer on the Necron Decurion detachment

So, I was a little bored at work today and a probability question has been bugging me for a while. What is the probability of killing Necron Warriors when they have a 4+ save, followed by a 4+ RP (Decurion) and re-rolling 1s due to the warlord being within 12 inches. The re-roll RP (Resurrection Protocol) rolls of 1 had been the bit that I was stuck on. So today I did some calculations on a spreadsheet to work things out.

TL DR, it takes approx 13 shots from a marine with a bolter to kill a warrior. Without the re-roll of 1s, it takes approx 12 shots to kill a warrior. Doesn't sound like much of a difference, but when you have a big blob of 20 warriors the maths looks a little more impressive. It takes approx. 262 bolter shots to kill all 20 warriors!!!! That is insane! Without the re-roll of 1s it takes a mere 240 shots. I suppose its still not a huge difference. The main point is that it takes an insane amount of shots to kill Warriors in a Decurion detachment. When you add in things like 3+ saves on Immortals or 3++ saves with RP on Wraiths you're in crazy territory. I haven't worked out the maths for that. Maybe tomorrow.

For anyone who cares here is the maths that led me to this.
Marine with bolter (or necron warrior) vs Warrior in Decurion.
Marine BS of 4, 2/3 shots will hit.
Strength 4 vs Toughness 4, 1/2 of hits will wound, so its now 1/3
4+ save, so 1/2 of saves will fail. So we're now at 1/6
4+ RP roll, so we're now at 1/12 shots will kill.
Now it gets tricky with the re-roll of 1s. 1/6 of failed RP rolls will re-roll, this is 1/24 of the shots fired. 1/2 of these will actually pass their re-rolled RP roll. Thats 1/48 shots will pass a re-rolled 1 RP roll. Adding 1/48 for the failed re-rolls to the.... oh damn my notes have failed me, I can't remember how I got to the next hurdle but I have 11/48 x 1/3 written down and I can't remember why now. I came to the answer of 11/144 chance of killing a warrior or 13.09 shots to kill it, which makes sense given the calculation below without the re-roll.

The maths for without the re-roll is a lot easier.
Marine BS of 4, 2/3 shots will hit.
Strength 4 vs Toughness 4, 1/2 of hits will wound, so its now 1/3
4+ save, so 1/2 of saves will fail. So we're now at 1/6
4+ RP roll, so we're now at 1/12 shots will kill.
Or 12 bolter shots to kill a warrior. 240 bolter shots to kill a blob of 20 warriors.

Without Decurion

Marine BS of 4, 2/3 shots will hit.
Strength 4 vs Toughness 4, 1/2 of hits will wound, so its now 1/3
4+ save, so 1/2 of saves will fail. So we're now at 1/6
5+ RP roll, so 2/3 will fail, we're at 2/18 or 1/9.
So it takes 9 bolter shots to kill a warrior not in a Decurion instead of 12. Makes quite a difference. Only 180 shots to kill 20 warriors (lol) compared to 240.

With guardsmen with lasguns against decurion warriors you may as well pack up and go home. To kill 20 warriors (without re-rolling 1s) it takes 480 lasgun shots! 24 shots to kill just 1 warrior.

I will try tomorrow to get the missing bit of math for the re-rolls. The end answer is still correct I believe, I just can't remember how I did the last bit of calculation.

I think the lesson to learn from this is don't bother trying to kill warriors with bolters because you will be rolling dice all day. The Decurion adds quite a chunk of extra resilience to and already resilient army for only the cost of loosing objective secured and being forced to take particular units. I don't think its much of a tax and having wraiths with a 3++ and a 4+ RP roll with 2 wounds at T5 is just plain wrong.

Like with any math-hammering and with my dice and rubbish dice rolling hands this will probably fail to stand the test of real life (real life toys anyway) battles.

Wednesday, 8 July 2015

First game of 7th edition wasn't so bad after all

On Monday night I played my first game of 7th edition 40k. I had made a simple list for my Necrons to ease me back into things.
HQ - Destroyer Lord with Warscythe
HQ - Destroyer Lord with Warscythe
Troops - 20x Warriors
Troops - 20x Warriors
Troops - 10x Warriors
Troops - 10x Warriors
Transport - Ghost Ark
Transport - Ghost Ark
Fast Attack - 6x Wraiths with 3x whip coils
Total - 1499 points

My warlord trait gave all models within 12 inches of the warlord Relentless and Crusader.

I managed to get a game with a guy practising with his Daemons for a tournament in October. He had Kairos, using the grimoire of true names for a 2++ re-rollable, some champions, 2 squads of pink horrors, some blood crushers and some plague drones. He had enough psychic power cards to wallpaper the room!

Deploying 6 numbered objective was a new thing for me and the fact that one player deployed them all.

I got first deployment and first turn. I deployed everything close together on the right hand side of my deployment zone. My destroyer lords were attached to the 20 warrior squads to give them preferred enemy, the 2 10 man squads were in the ghost arks behind the big squads, to regenerate any losses, and the wraiths were deployed on the right hand side.

He deployed his forces stretched out along his deployment line. His fatal error at this point was deploying Kairos opposite the wraiths, hidden behind ruins, but opposite them none the less.

The entire battle basically involved him summoning daemons and me shooting and killing them. He had a few shooty psychic powers but these didn't do much. 40 rapid firing gauss shots that re-roll 1s to hit and to wound made a mess of anything that went near my army. He deepstruck his big squad of plague drones near one of the squads of 20 and I shot them and then charged them (due to relentless) and made a mess of them. Necron warriors charged something and won combat!

My wraiths charged up the side of the board and by turn 2 were in combat with Kairos. This seemed like a waste of the wraiths as they couldn't really hurt him due to his 2++ re-rollable but it was a major game changer. Kairos is utterly crap in combat, 1 attack and 1 WS. The wraiths spent 3 game turns locked in combat with him and only knocked off 2 wounds. He charged the wraiths with plague bearers with 2 champions in the squad, and the wraiths just kept shrugging off the wounds. By the end of turn 4 there was one wraith left in combat with Kairos, plague bearers, 2 nurgle champions, a squad of horrors and a nurgle greater daemon had just been summoned next to the combat. The rest of the table however was at this point devoid of any other daemons. He had summoned bloodletters, blood crushers and other things and they were all dead too. My army had lost 5 wraiths and 4 warriors..... He threw in the towel at this point, quite understandably.

Objective wise I had got First Blood, I killed a squad in a shooting phase and I held an objective. He had only held an objective. The new objective system is certainly different now, with the getting 3 cards and changing them whenever they're achieved etc. Its a more interesting way of doing things compared to the old end of game objectives but I do think they're a bit messy. My other two objectives which I didn't achieve were, kill a monstrous creature and kill the enemy warlord. The only way I could get those were to kill Kairos with his damn 2+++ save. God I had that combo.

So I won my first game of 7th. Wasn't expecting that. I don't know what I was so worried about. There are a few changes but it is still more or less the same game as 6th edition. I'm not sure if I like the objectives and I still don't like the way psychic powers work with their randomness and cards everywhere, I prefer the old style where they're basically like wargear with a perils of the warp test.

Once I started moving models and shooting stuff it was as if I had never stopped playing. It all came back so quickly. Now I'm looking forward to next Monday and my next game of 40k. Maybe using my scarab farm this time.

Sunday, 5 July 2015

OMG, I'm back!


After nearly 2 years to the day of not posting I'm back. I have been on hiatus from 40k for a variety of reasons, mainly because it stopped being fun and then 7th changed 40k beyond recognition for me. I have spent 2 years working on model railways instead. Which was relaxing and there was no pressure to win win win. 

Well, I have now moved due to work and there is a wargaming club where I have been sent. So against my better judgement, I find myself sliding back into it. I'm a little bit miffed about the costs of simply getting back into it though, 1 codex and the rulebook is all I need. Just that comes to £80!!! WTF!! I have found a cheap rulebook on ebay for £20 but I think I'll have to pay full whack for the necron codex. I have access to the necron codex though and I'll write up a list and see if I can get a game at the club tomorrow night. 

So much seems to have changed since 6th edition 40k and the old codex. I don't have a clue what the deal is with formations and pretty much everything seems to have been tweaked or changed. My flayed ones might actually get deployed at some point now, I just have to find them all in the loft and reattach various arms that have come off. 

I think I'll start off with a simple army to get back in the swing of things. Lots of warriors, a destro lord to lead a big squad of them for preferred enemy, a couple of ghost arks and some wraiths if I have spare points.

So much stuff to try and take in. There are 4 new armies since I stopped playing... how did that happen??