I have been able to identify this still taken from film according to Mr. JINNO Masami's "Aircraft Carrier ZUIKAKU" book that deals with her loss.(ISBN4-7698-1026-1)
On page 43, this B6N is identifed as taking off from ZUIKAKU during September 1944 with the crew consisting of Ltjg. NAKAHARA Michio (Yo 9 Reserve)- Pilot: W.O. SANO Michio (Ko 3)- Observer: PO1 OKAZAKI Teruo (Otsu 15)- Gunner.
This is during workup and note that the "NAKA" symbol is the first character in the pilot's family name.