Kongou is a Granny IRL, considered her being pre-WW1 battlecrusier. She might be the oldest warship still in commission for Japan during WW2.
Ships like Asashi (pre-dread turned repair ship, laid down in 1898), Tokiwa (armored cruiser turned minelayer laid down in 1897), Izumo&Iwate (armored cruisers, both laid down in 1898) and Yakumo (armored cruiser, laid down in 1897) were significantly older than her and still in active service (albeit not in frontline roles) during WW2.
