Plans: Corruption

Source
These plans are picked up while opening Blacksmithing Plans while in Stratholme. The plans are near the second ziggurat.

Taking these plans summons a Black Guard Swordsmith. This skeleton must be defeated to complete the quest, as part of the requirements to gain the swordsmithing sub-specialization of Weaponsmithing (Blacksmithing).

As of October 6, 2008, this item had been confirmed as broken by several in game technical assistance operatives. had not dropped from the Blacksmithing Plans in Stratholme or anywhere else since the removal of the Weaponsmithing quest lines at the advent of the Burning Crusade. There was no proposed intent to re-introduce this item into the game, however the item began dropping again after the 3.0 patch.