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Leutnant zur See (Lt zS or LZS) is the lowest officer rank in the German Navy, grouped as OF1 in NATO.
The rank was introduced in the German Imperial Navy by renaming the former rank of Sekonde Lieutenant in 1890. In navy context officers of this rank were simply addressed as Herr Leutnant. To distinguish naval officers from officers of the army, the suffix zur See (at sea) was added in official communication, sometimes shortened to z.S. or Lt.z.S. The rank has since been used by the Reichsmarine, the Kriegsmarine and the German Navy. In the Volksmarine the rank was originally used in the same way until the suffix zur See was dropped.