You write, “the hinomaru was not painted, but made up of pieces of painted canvas tacked to the deck, which could be moved around?
Actually many IJN ships, particularly cruisers and submarines had large canvas flags which they would cleat to one of the forward main gun turrents (in the case of capital ships) or to the conning tower of the subs for purposes of IFF. I do not recall that any mention has been made in the literature that this occurred on carriers, but it is logical that this may have been done on occasion.
