No. 23 Nitto Maru was a small iron fishing boat of the Nitto company, launched in 1935. The builder is given as Fuji. She was about 30 meters long. The raid account calls her a 70-ton boat. A ship list gives 90 gross tons. In December 1941 the navy took her up as a special picket and based her at Ominato, with the 5th Fleet's No. 7 Patrol Division. Her reports went to the light cruiser Kiso. She carried a radio and a 13.2 mm machine gun. The name of the man in charge of her is not recorded.
On the morning of 18 April 1942 she was still a long way from Japan, on the outer picket line. At 7:38 she sighted Task Force 16 and got a warning onto the air. The raid account puts the force about 650 nautical miles out. Another figure for her patrol that morning is 668 nautical miles, near 35 degrees north and 154 degrees east.
She was sunk that morning. One account says Nashville sank her with gunfire after the message had gone out, and that five of her eleven men were picked up. A history of the raid says the cruiser fired more than 900 shells in a rough sea and that she went down about 8:23. The Dictionary history of Nashville says planes from Enterprise sank the boat that radioed, and that Nashville's guns sank a second scout. Another account says Enterprise planes damaged No. 23 Nitto Maru and a second picket, and that Nashville's guns then sank both. Which ship fired the shells that finished her is not one settled credit. A second list gives her eight men, not eleven.