In 1939 the German Supreme Command officially passed the code-named "Z" large-scale shipbuilding program, "Z plan" officially launched. Plans will enable Germany through the implementation of nearly 10 years of large-scale shipbuilding program, and ultimately have the challenge to the most powerful of the strength of the sea.
Z program is the core of two large battleships, one of which is Bismarck class battleship, another level: H-class battleship.
The planned H-Class battleship design began in 1937, when a total of six were expected to be built. The first ship H39 started in 1939, the year on July 15 officially laying keel. However, on October 10 that year was suspended for the construction of U-submarines. Due to shortage of raw materials and the beginning of World War II so there is no H-class battleships.