Interesting question ...
A quick peek into Groener ("Die Deutschen Kriegsschiffe 1815-1945") indicates that 3-shaft propulsion was a feature of German capital ship designs starting with the Kaiser Friedrich III class of pre-dreadnoughts dating back to 1895 (laying down of first ship in class). This trend appear to have continued (with the sole exception of Prinzregent Luitpold with 2-shafts) all the way to the Bismarck class. The post-Bismarck design projects (H, J, K, L, M, N) had 3-shaft diesel propulsion, while the later designs (H42, H43, H44) had 4-shafts.
The German WW1 battle-cruisers (all the way through the uncompleted Mackensen and Ersatz Yorck designs) featured 4-shaft propulsion.
The post-WW1 diesel powered "pocket battleships" (Graf Spee, Deutschland) featured two shafts. The WW2 era "light battleships" (Scharnhorst, Gneisenau) and the heavy cruisers (Bluecher, Hipper Prinz Eugen) all featured three shafts.