Double strikes are a unique characteristic of daggers. A double strike hits the target twice in one attack. The damage and chance to hit for each strike is calculated separately. Successful Dual Attacks always result in double strikes (triggering any effects of the skill twice).
With 0 Dagger Mastery, the character's chance of executing a double strike with daggers is 2%; this increases an additional 2% for each rank in the attribute, e.g. rank 12 provides a 26% chance.
The extra attack means that double strikes have the same impact as increasing the attack rate for daggers. For example, at Rank 4 (10% chance to double strike), daggers would get the equivalent of 1.1 attacks every 1.33 sec instead of their normal 1.0 attacks. To oversimplify, each additional rank increases the effective attack rate by slightly less than 2%.
Dagger Rank Sword§ 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Double Strike Chance 0% 2% 4% 6% 8% 10% 12% 14% 16% 18% 20% 22% 24% 26% 28% 30% 32% 34% 36% 38% 40% 42% Net Attacks/Sec 0.75 0.77 0.78 0.80 0.81 0.83 0.84 0.86 0.87 0.89 0.90 0.92 0.93 0.95 0.96 0.98 0.99 1.01 1.02 1.04 1.05 1.07 Effective Attack Interval 1.33 1.30 1.28 1.25 1.23 1.21 1.19 1.17 1.15 1.13 1.11 1.09 1.07 1.06 1.04 1.02 1.01 0.99 0.98 0.96 0.95 0.94
- § Swords are shown for comparison; they have the same base rate of attack without a chance of double-strikes.