A rare video of a Type 97 Large Flying Boat or Kawanishi H6K "Mavis" from the NHK news collection, dated April 20, 1944.
The "Mavis" in the video is carrying the remains of Major Otowa Tadahiko who perished in February of the same year during the battle for Kwajalein island together with 6,500 soldiers. Present in Yokosuka were his father Prince Asaka-no-miya Yasuhiko and his brother Prince Takahiko.
Unfortunately the "Mavis" tail marking is not clearly visible. Nevertheless note the Kato tractor and the waterproof clothes of the ground crew members.