[3] Propulsion was by 12 Kampon boilers driving four sets of single-impulse geared turbine engines, with four shafts turning three-bladed propellers.

[3] Chōkai's main battery was ten 20 cm/50 3rd Year Type naval guns, the heaviest armament of any heavy cruiser in the world at the time, mounted in five twin turrets.

At the start of the Pacific War, Chōkai supported the invasion of Malaya and participated in the pursuit of the Royal Navy's battleship Force Z.

During January and February 1942, Chōkai was involved in operations to seize the oil-rich Dutch East Indies and the island of Borneo.

On 1 April 1942, Chōkai left Mergui to participate a raid on merchant shipping in the Bay of Bengal.

The battle of Savo Island was one of the most devastating Japanese naval victories of the war, the four allied heavy cruisers sunk and several more ships damaged or crippled.

For the rest of the Solomon Islands campaign, Chōkai would fight in an assortment of night battles with the U.S. Navy, sustaining varied, but mostly minor, damage.

Relieved as the Eighth Fleet flagship shortly after the final evacuation of Guadalcanal, Chōkai headed back to Yokosuka on 20 February 1943.

Chōkai was then transferred to Cruiser Division Five, where she survived an air attack on 24 October 1944, while the battleship Musashi was sunk.

[8][9][better source needed] An explosion was observed aboard Chōkai before a TBM Avenger from the USS Kitkun Bay dropped a 500 lb (230 kg) bomb on her forward machinery room.