Following on from the four ship Nassau class, the Germans go on to the four ships of the Helgoland class with 8x12", five Kaiser class (included a fleet flagship) with 10x12", and the four Konig class with 8x13.8".
The follow on Kaiser class were to be armed with 10x12", the 12" gun the Germans believed was superior to the British 12"/13.5" guns. Various layouts were studied before the triple aft layout was chosen.
The Germans finally upgraded to a gun that would be noticeably superior to the current British builds with their 13.5" guns. The Konig class had hardly been laid down in 1911-12 when news that the RN was going to 15" weapons, and the Germans had to move on to the Bayern class ships to keep up.