Sea mines. Terrible weapon. Sea mines were widely used during the Russo-Japanese War. During the First World War, all the warring fleets installed 310 thousand sea mines, which sank about 400 ships, including 9 battleships. ⠀ Russia was not only the first to create sea mines and use them, but also achieved concrete military results. The British officially recognized the high-precision use of minefields in the Russian fleet. And the famous German submariner Ernst Hashagen wrote that during the First World War, only the mines of one country - Russia - posed a real danger. ⠀ Many scientific developments of Russian inventors in the field of sea mines remained unrealized, primarily because they were far ahead of the technical capabilities of their era.