I take some time to look at the math behind the upcoming Wolf Claws to help you decide whether to re-roll to-hit or to-wound.
No matter how much I'm looking forward to modeling up and playing a Gears of War themed Guard army, I will always have a soft spot for my Space Wolves. I love their fluff, I love their playstyle and I'm going to love them more once they arrive in October.
Of some interest to me are the Wolf Claws, the Space Wolves version of Lightning Claws. According to several rumor sources, these will allow you to choose whether to re-roll the to-hit roll or the to-wound roll. The question is, which is better? Let's take a look:
Single Dice Rolls and Re-rolls
The image above shows for each dice roll the normal percentage, the additional chance by re-rolling it, and the total change of success. This is the basis for the following table, which compares all of the dice rolls in close combat:
First, the terminology: when you see 3+r | 2+, that means 3+ to hit with a re-roll, followed by a 2+ to wound. So on the first row, you can see that if your roll is going to be a 3+, then a 2+, it's better for you to re-roll the 3+. Second, you can see that for rows where the requirement is the same (3+ to hit and to wound, for example), it makes no difference. That's simply rules of math: 3 x 2 is the same as 2 x 3.
Obviously, if you look at the chart for just a little while, you'll see a pattern emerging: in all of the comparisons, the re-roll is best utilized when it is used for the roll least likely to succeed. So given the choice between re-rolling a 4+ or a 2+, you want to re-roll the 4+.
Of lesser but still notable importance: how often are Wolf Claws advantageous over Lightning Claws and by how much? If you look at the chart, you'll see that of the 15 roll combinations there are six cases where they make a difference. And where the choice to re-roll to hit instead of to-wound is advantageous, the gain ranges from negligible (about 2.8%) to reasonable (about 13.9%).
Usage and Bottom Line
In gameplay, the Space Wolves player will want to do some quick thinking ahead before the dice are rolled to determine which roll will be more difficult and then declaring the re-roll to be that one. So if you will have to roll a 4+ to hit, then a 2+ to wound, re-roll the hit. But if you're rolling a 4+ to hit, then a 5+ to wound, re-roll the wound.
Wolf Claws are a fun and solid addition to the Space Wolves arsenal of weapons, and the re-roll choice they provide should always be used to re-roll the harder and I look forward to seeing them shred up enemies on the field of battle!