State of the League

Week 3 has begun! 5 games until the playoffs!
PlayerTeamTVW-L-D
SBHieroglyphic Honkies (Khemri)12703-1-1
AustinYoloin Biatches (Amazons)15103-1-0
SeanSorin's Team (Halflings)11503-2-0
AliseKillogg's (Amazons)11903-1-0
JeffInvalid team name! (Orcs)11302-2-0
PiRuby for Vigor (High Elves)14402-2-1
MojoTurtle Turtle (Lizardmen)11301-3-0

Saturday, March 16, 2013

Advanced Tactics: Injuries

Everybody comes to a game of Blood Bowl looking for some heads to roll. The fans want to see blood spill and, although they may be loathe to admit it, both coaches are aiming to put enemy players in the ground. Conversely, nobody likes to lose players, but if you're looking to run with the same 11 men on the field forever you might want to go play Madden or something. I might write another post in the near future about how best to preserve your squad, but today we're talking all about the opposite.

How To Lose Friends And Injure People
I've talked about the math on injuries a bit in previous posts, but here's a refresher. Whenever a player gets fouled or falls down because of a block result (unless Wrestle was used), a failed dodge, or a botched GFI, a 2d6 armor roll is made for that player. If the result of the roll is higher than the player's armor, then a 2d6 injury roll is made for the player, using this result table:

2d6 Roll% of OccuranceResult
2-758Stunned
8-925KO
10-1217Casualty

Obviously, you want to get that casualty result as often as possible. It helps with your short-term goal of winning the game by removing an opposing player from the field and it helps with your long-tem goal of team improvement by awarding your player SPP. There are two ways to significantly improve your casualty rate: making better blocks and developing players to cause injuries. (Smart fouling will also help to cause casualties, but there's already a post about that.)
Making better blocks is a little bit complicated. The simplest part is covered here (tl;dr: rolling more dice is good and also Block and Tackle are valuable in the relevant situations), but the more difficult bit--positioning your players and sequencing your actions such that you produce the maximum number of multi-die blocks each turn of the drive--is a bit beyond the scope of this post. Just remember to always have a drive-long strategy in mind when moving and blocking; if you're not thinking about the next turn and the turn after that, you're often going to find yourself losing to an opponent who does. Skill pickups that can help make your blocks better include Guard, Tackle, and Dauntless.
Developing players to cause injuries, on the other hand, is very much within the scope of this post. The most common skill for increasing a player's killing power is Mighty Blow, the influence of which can be seen in this handy visualization:


Players with the Claw skill treat all enemies as though they are AV 7, which is obviously valuable. It also has a favorable interaction with Mighty Blow, producing the following graph:


The other skill that interacts quite well with Mighty Blow is Piling On, which allows a player to throw himself on top of an enemy that he has just downed in order to reroll either the armor or injury roll for that player. This skill is a little bit less of a no-brainer because it leaves the attacking unit prone, which can range from mildly inconvenient to incredibly dangerous (particularly if the Piling On player is someone valuable that the opponent might like to foul). In order to get the most out of Piling On, you have to know the math (surprise!). In the following chart, the red line represents your percentage chance of causing an injury if you use Piling On any time you fail to injure a downed opponent, while the blue line represents your chance of causing an injury if you use Piling On only to reroll the injury roll after breaking armor:


As you can see, Piling On provides a tremendous improvement over the base casualty rate. What's important to note, though, is that the improvement in the injury rate between the red and blue lines is actually quite small. At AV 6 and 7, using Piling On to reroll failed armor breaks only improves the casualty rate by ~4%, and the effect is reduced significantly as AV climbs (or falls).
Because Piling On leaves your player prone after he has taken his action for the turn, using it significantly reduces that player's usefulness over the next turn. He won't provide any tackle zones during the opponent's upcoming turn and he'll be vulnerable to fouls, and then on your next turn he won't be able to throw another block without using up your blitz (unless he also has Jump Up, which would be unusual but might be something worth thinking about for a player like this). This means you really need to get some value out of knocking him prone, so think carefully about the numbers here before telling him to drop the elbow.
Incidentally, Piling On also interacts pretty favorably with Mighty Blow:


Making A Monster
At this point, the data has made it clear that the most effective killers will have Mighty Blow, Claw, and Piling On, allowing them to cause a casualty on ~20% of their knockdowns. There aren't any positions that start with even two of these skills, however, so you're going to be stuck building your own brutalizer. So in what order do you take the skills to ramp up your killing power as quickly as possible?
The math indicates that Mighty Blow is actually the most important skill. It provides the largest increase in casualty rate on targets with AV 8 or lower and is only slightly less effective than Claw on targets with AV 9. (Claw remains the head-and-shoulders standout against AV 10, but you're not going to run into much of that.) Mighty Blow is so effective, in fact, that it increases casualty rates on blocks even more than improving the block's chances of success; getting an extra successful face--using Block against a player without Block or using Tackle to cancel someone's Dodge--and getting an extra die on the block are both significantly less effective for injuring people than just adding Mighty Blow to your player. Piling On is the runner-up, again increasing casualty rates significantly more than actually improving the quality of your blocks although, like Mighty Blow, it's less effective than Claw against AV 9 and 10 players. (Of course, improving the quality of your blocks knocks opposing players down a lot more, and there's obviously a lot to be said about the value of that even when it doesn't result in a casualty.)
A final note about creating your own killer: Mighty Blow and Piling On are both from the Strength category, and Claw is from the Mutation category. You'll want Strength access on normals on a player that you intend to turn into a casualty machine, and many of these players just won't ever have access to Claw. If you're looking for players that can easily assemble the unholy trinity of smashing skills, the list is fairly short: Chaos Pact Marauders, Khorne Bloodthirsters, Norse Yhetees, Nurgle Warriors and Pestigors, Underworld Blitzers and Trolls, and every player on the Chaos team. Most players on the Underworld and Chaos Pact teams can get there with one double and Skaven Blitzers and Rat Ogres can do the same, while Necromantic Werewolves need two doubles. Be careful about using Piling On on a big guy, though, as their negative traits can make it relatively difficult to get them back up easily and your opponent may be more than happy to gang-foul them while they're down!

The only question left is "Just how much better is one of these teched-out slayers than the average fresh-off-the-assembly-lineman?"