The three K-class Light Cruisers were the first modern cruisers of the German navy after World War I. For the first time, the main artillery of a German CL was mounted in real turrets and not in single mounts as before.  An interesting detail was that the afterwards turrets were mounted off the centerline to give them a better arc of fire. The preserve weight, about 85% of the hull was welded, but this causes one of the major drawbacks for those ships, their structural weakness.

With the idea of commerce war in mind, those ships should have been used in the North Atlantic, but their much too short endurance and structural problems made this kind of duty impossible.
The first of the three ships, the Kreuzer B (later Königsberg ) was laid down on April 12th 1926 and completed three years later. The Kreuzer C (Karlsruhe ) joined the fleet in November 1929 while the Kreuzer D (Köln ) was commissioned in January 1930.

All three cruisers made several voyages in many countries of the world before World War II  to "show the flag". During the war they did see action in the North and Baltic Sea. Two of them were sunk during Operation "Weserübung", the invasion of Norway,  while the third was sunk at the end of the war.