Catan: Cities & Knights (German: Städte und Ritter), formerly The Cities and Knights of Catan, is an expansion to the board game The Settlers of Catan for three to four players (five to six player play is also possible with the Settlers and Cities & Knights five to six player extensions; two-player play is possible with the Traders & Barbarians expansion).
A city on wool, ore, or wood, produces one corresponding resource as well as one corresponding commodity (cloth, coin, or paper).
In total there are 36 commodity cards: 12 paper (from forest), 12 cloth (from pasture), and 12 coin (from mountains).
At the third level, players earn a special ability, depending on the type of improvement.
Knights are units that require continuous maintenance through their activation mechanism, but have a wide variety of functions.
Knights are placed on the board in a similar manner to settlements, and can be used to block opposing roads, active or not.
These actions include: If a knight is promoted or forced to retreat, its active status does not change.
When the barbarians arrive at Catan, a special phase is immediately performed before all other actions (including collecting resources).
In this special phase, the barbarians' attack strength, corresponding to the combined number of cities and metropolises held by all players, is compared to Catan's defense strength, corresponding to the combined levels (i.e. 1 point for each basic, 2 for each strong, and 3 for each mighty) of all activated knights in play.
If the barbarians are successful in their attack (if they have a strength greater than Catan), then the players must pay the consequence.
If they only have settlements, or metropolises, then they are immune to barbarians and do not count as the player contributing the least defense.
Regardless of the outcome, all knights are immediately deactivated, and the barbarian ship returns to its starting point on the track.
Instead, each of the tied players draw a progress card (explained below) of the type of their choosing.
Because of the mechanics of progress cards explained below, one of the two white dice used in Settlers is replaced by a red die.
Higher levels of city improvements increase the chance that progress cards will be drawn, with the highest level of city improvement allowing progress cards to be drawn regardless of the value on the red die.
While this clarification is not overtly stated in the Cities & Knights rule book, it is enforced in the online version of the game.
Both the victory point and the trade privilege are lost if another player takes control of the merchant.
The top of the chart has the standard costs from the Settlers game (for settlements, upgrade to city, and roads).
Each segment, as it is flipped down, also shows the updated dice pattern needed to earn the player a progress card in that category.
This being said, it's also hard to imagine a knight on a horse holding a cannon in his arms and firing it in all directions... "[3]