[MENTION=29172]FireShark[/MENTION] ; Yes, indeed I put on the Premium camo just to confuse you! :P But I know you'll get the answer anyway! Though there was a massive hint that you didn't notice that could have helped you!
Now you know why Hiryuu, Souryuu, Akagi, Kaga, Shoukaku and Zuikaku had those katakana on their costume, because in their real life counterpart those was also present, also the reason why Akagi/Kaga/Hiryuu/Souryuu have it nearer to the lower half of the body whereas Shoukaku/Zuikaku have it near their shoulder, its because those letters are located near the front for Shoukaku/Zuikaku and near the back for the other 4 :3
P