PHILIPPINE SEA (Sept. 25, 2020) The Los Angeles-class attack submarine USS Chicago (SSN 721) transits the Philippine Sea in support of Valiant Shield 2020. Valiant Shield is a U.S. only, biennial field training exercise (FTX) with a focus on integration of joint training in a blue-water environment among U.S. forces. This training enables real-world proficiency in sustaining joint forces through detecting, locating, tracking and engaging units at sea, in the air, on land and in cyberspace in response to a range of mission areas. (U.S. Navy video by Mass Communication Specialist 2nd Class Erica Bechard)