Prior to the English 4th edition (2nd international edition) of Cities & Knights, a city may be sabotaged through the use of the Saboteur progress card, forcing a city to collect resources as if it were a settlement.
Gameplay
A sabotaged city is represented by placing a city piece on its side. Note that the design of international edition city pieces since the 2nd international edition makes placing them on their side difficult. Note that sixth settlements are also represented by placing a city piece on its side; care must be taken to distinguish the two.
Whenever a hex produces resources, players with adjacent sabotaged cities collect one resource instead of two resources, or one resource and one commodity, as appropriate.
A player may not sabotage their own cities.
Sabotaged cities are still worth two victory points, and contribute to barbarian strength during a Barbarian Attack. Any City Walls present in a sabotaged city continue to function.
A player may have any number of sabotaged cities. A player may continue to upgrade settlements to cities even if one of their cities is sabotaged.
A metropolis may not be sabotaged. The rules do not dictate whether a sabotaged city can become a metropolis.
Sabotaged cities may be repaired as a build action, by paying 1 lumber and 1 ore per sabotaged city.