A Yokosuka D4Y1-C "Suisei" (Judy) belonging to the 121 Kokutai is having the Atsuta engine checked. Location is Katori base, Chiba prefecture, during the winter of 1943-1944.
The 121Ku was organised on October 1, 1943 as the first land-based reconnaissance unit of the IJNAF. Originally based in Katori it was equipped with "Suisei" and Nakajima C6N "Saiun" (Myrt) with a total of 12 aircraft in its strength on October 1, 1943. By January 1944 the number of aircraft became 24 and a month later reached its peak with 48.
At that time, February 1944, the unit relocated to Tinian, in the Marianas and to Peleliu, in the Palau, where it became the main reconnaissance unit of the 1st Air Fleet.
From June 1944 the unit participated in the Operation A-Go in the course of which lost its aircraft. The unit was disbanded on July 10, 1944 and the remaining members fought as foot soldiers in the battles for Tinian island where they lost about 70 members and the battle for Peleliu where only five survived.
The unit used the kanji "雉" (kiji) meaning "pheasant" from October 1943 until January 1944. After that date they used the number "21".
The aircraft in the background has the "kiji" on its tale while the kanji on the fuel truck says "龍" (ryu) - dragon.