Blockade of Germany
The British established a naval blockade of Germany early in the war. As was shown later in the Battle of Jutland, the German fleet could not defeat the British fleet to break the blockade. The blockade was unusually restrictive in that even food was stopped, as it was said to help the war. The Germans regarded that as an attempt to starve the German people into submission. They wanted to fight back and so blockaded Britain and France.