The Japanese renewed the attempt on a great scale and with utmost intrepidity, at Port Arthur; but though a steamship can move with a speed and precision impossible to a sailing ship, and can therefore be sunk more surely at a chosen spot, the experiment failed. Neither Americans nor Japanese succeeded in preventing their enemy from coming out when it wished. Development of Dreadnoughts As the 19th century came to a close, the familiar modern battleship began to emerge; a steel-armoured ship, entirely dependent on steam and carrying a relatively small number of large guns mounted in turrets, typically arranged along the centreline of the main deck. The revolutionary Dreadnought of 1906 was the first battleship to almost entirely dispense with smaller guns and used steam turbines for her main propulsion. The Dreadnought rendered all existing battleships obsolete, because she was larger, faster, more powerfully armed and more strongly protected than existing battleships, which came to be known as pre-Dreadnoughts. This sudden levelling of the field led to a naval arms race as Britain and Germany and, to a lesser extent, other powers like the United States, France, Russia, Japan, Italy, Austria-Hungary, Turkey, Brazil, Argentina and Chile all rushed to build or acquire Dreadnoughts. The First World War The introduction of mines, torpedoes and submarines greatly increased the complexity of naval tactics during the First World War. Even so, the gun remained the principal naval weapon. It could still deliver its blows at the greatest distance in the greatest variety of circumstances. Fleet tactics The development of long-range guns mounted in turrets changed the nature of naval tactics. While concentration remained a fundamental objective of tactics, the increased range and field of fire of naval guns meant that admirals now sought to achieve concentration of fire, rather than concentration of ships. The aim of a skilful officer was to concentrate a superior force on a part of his opponent's formation. In the age of sail, when the range of effective fire was a thousand or twelve hundred yards and guns could only be trained over a small arc because they were fired out of ports, concentration could only be effected by bringing a larger number of ships into close action with a smaller. By the early 20th century, when gunfire was effective at 7,000 yards or more, and when guns fired from turrets and barbettes had a far wider sweep,