Complex sentence: On 16 December, months ahead of schedule, the battleship was formally commissioned at Kure, in a ceremony more austere than usual, as the Japanese were still intent on concealing the ship's characteristics.
Split into simpler sentences: On 16 December, months ahead of schedule, the battleship was formally commissioned at Kure. The ceremony was more austere than usual; the Japanese were still intent on concealing the ship's characteristics.