The Battle of the Philippine Sea was fought 19-20 June 1944 in the waters west of the Mariana Islands by elements of the Imperial Japanese Navy's Combined Fleet and of the United States Navy's Pacific Fleet. The battle exacted a terrible toll from the Japanese naval air arm, costing them most of their few remaining experienced pilots. The Combined Fleet was no longer capable of serious offensive operations after this engagement. Historian Samuel Eliot Morison characterized it this way: Since the Japanese assumed the tactical offensive, their forces are listed first. Japanese forces