i've imagine when some other ship that not revealed yet, but was existing in world war 2...
IJN Taiyo : http://en.wikipedia.org/wiki/Japanese_aircraft_carrier_Taiy%C5%8D
IJN Shinyo : http://en.wikipedia.org/wiki/Japanese_aircraft_carrier_Shin%27y%C5%8D
IJN Kaiyo : http://en.wikipedia.org/wiki/Japanese_aircraft_carrier_Kaiy%C5%8D
what do you think?? an event maybe??