Map overlay documenting the activities of Japanese submarines from May 31 to June 6, 1945. The overlay contains annotations regarding the USS Jack (SS-259), USS Barb (SS-220), German U-boat U-181, U-boat U-862, U-boat U-195, U-boat U-219, submarine UIT-24, submarine UIT-25, Japanese submarine I-13, submarine I-14, submarine I-47, submarine I-49, submarine I-53, submarine I-58, submarine I-101, submarine I-121, submarine I-122, submarine I-155, submarine I-156, submarine I-157, submarine I-158, submarine I-159, submarine I-162, submarine I-165, submarine I-201, submarine I-202, submarine I-204, submarine I-351, submarine I-367, submarine I-368, submarine I-371, submarine I-372, submarine I-400, submarine I-401, submarine I-402, submarine I-405, submarine HA-101, submarine HA-102, submarine HA-103, submarine HA-104, submarine HA-106, submarine HA-108, submarine HA-109, submarine HA-201, submarine HA-202, submarine RO-57, submarine RO-62, submarine RO-63, submarine RO-64, submarine RO-67, submarine RO-500, submarine RO-50, submarine HA-107, submarine I-363, submarine I-36, submarine RO-50. Significant events visible on the map include the USS Barb sighting a conning tower.