Text (IA+errata): Cumulative Upkeep - Pay {B} and 1 life. ; If a land is tapped for mana, it produces {B} instead of any other type. [Oracle 2007/10/01]
All affected lands produce just one black mana regardless of how many it might normally generate. [Duelist Magazine #6, Page 131]
Will remove restrictions on how mana generated by the land is used. [Duelist Magazine #6, Page 131] For example, the black mana from a Mishra's Workshop can be used for any purpose.
The ability generates a replacement effect (see Rule 614). [DeLaney 1998/11/03]
