Ignore Target Defense

Ignore Target Defense does exactly what it says: it ignores a target's defense so that DR = 0. With ITD, the To-Hit formula used to determine the chances of an attacker hitting a defender is changed from this:

100 × AR/(AR + DR) × 2 × alvl/(alvl + dlvl)

but ITD changes the formula to:

100 × AR/(AR + 0) × 2 × alvl/(alvl + dlvl) = 100 × 1 × 2 × alvl/(alvl + dlvl), which is shortened to this:

200 × alvl/(alvl + dlvl).

So what does this mean? Well, let's take the bowazon from the Attack Rating section: a clvl-69 amazon with 300 dexterity, slvl-10 Penetrate, a Witchwild String short siege bow, and 500 AR from equipment. According to the previous example, she has ~4,433 AR. Let's say she's trying to attack a mlvl-70 monster with 1,000 DR

100 × 4,433/(4,433 + 1,000) × 2 × 69/(69 + 70) = 100 × 4,433/5,433 × 2 × 69/139

but ITD means that DR = 0 which changes the formula to:

100 × 4,433/4,433 × 2 × 69/139, which is shortened to this:

200 × 69/139.

Note that ITD only works on normal monsters: it doesn't work on players, champions, uniques, or super uniques. In addition, the modified equation still takes the most important part of the To-Hit equation - the levels of the attacker and defender - into account, so you can't use ITD weapons to counter a level disadvantage.

Where can I get Ignore Target Defense?

Equipment:

Eaglehorn Crusader Bow

Widowmaker Ward Bow

Malice (rune word weapon)

Hand of Justice (rune word weapon)

Sockets:

Jah rune: ITD when inserted into a weapon