US fighter jets flew over the waters in the western Pacific Ocean, while the nuclear-powered aircraft carrier Ronald Reagan joined Japanese destroyers and a Canadian warship in the biggest combat drill on Japan.
Japan and the United States have mobilized 57,000 men from the navy and air force to take part in the biennial Sword War games.
That number is 11,000 more than the 2016 exercises, which simulated air combat, amphibious landing and ballistic missile defense training.
"We are here to strengthen our capabilities in anticipation of the need," Admiral Carl Thomas, commander of the US aircraft carrier, said in a press statement on board the carrier while drills like the sword were exactly what we needed.
Eight other ships joined the anti-submarine training, in a show of strength in waters that Washington and Tokyo fear is growing Chinese influence.
"The US-Japan alliance is key to the stability of the region and the broader Indian Pacific region," said Admiral Hiroshi Ijawa, commander of Japanese ships aboard the US aircraft carrier.
A Canadian supply ship is also involved in the "swordhead" maneuvers, along with the frigate that sailed with the Reagan aircraft carrier.
