PACIFIC OCEAN (Sept. 15, 2020) Lt. Sungwoo Jung, the assistant operations officer and quality assurance officer aboard the Los Angeles-class fast-attack submarine USS Chicago (SSN 721), from San Diego, looks through the periscope during 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 photo by Mass Communication Specialist 1st Class Derek Harkins)