Okinawa Campaign: April 1-June 21, 1945
https://www.history.navy.mil/content/history/museums/nmusn/explore/photography/wwii/wwii-pacific/okinawa.html
7ID and Operation Iceberg: It All Began With the Invasion of Okinawa on April 1, 1945
https://www.army.mil/article/255269/7id_and_operation_iceberg_it_all_began_with_the_invasion_of_okinawa_on_april_1_1945