Nobunaga master plan? `MURICA BABY.
(yes I know the united states didnt even exist at that time, I am making a joke please dont go "AKTUALLY AT THE TIME JAPAN EXPERIENCE WITH CANNONS WHERE FROM EUROPEAN SHIPS ETC.ETC.ETC.")
I think it's pretty innovative of the Oda to come up with these behemoths here (1578). The concurrently equivalent would be the galleasses, most notably being instrumental at Lepanto (1571).