Why Ibuki was called a battle cruiser

Were the Ibuki-class ships battle cruisers or armoured cruisers?

They began as armoured cruisers, but Japan adopted the battle-cruiser label to advertise modernity and strengthen its claim to capital-ship treaty tonnage.

Ibuki began in the armoured-cruiser lineage before receiving the battle-cruiser label. The ships were built alongside the dreadnought revolution, and one used turbine machinery, so the newer name advertised technological modernity. Their 12-inch and 8-inch armament also made them formidable against contemporary armoured cruisers. Calling them battle cruisers strengthened Japan's effort to have them recognized within its capital-ship allowance, showing how classification could serve diplomatic strategy as well as technical description.