was a heavy cruiser, armed with ten guns, four guns, eight tubes for the Type 93 torpedo, and assorted anti-aircraft guns. Named for Mount Chōkai, Chōkai was designed with the Imperial Japanese Navy strategy of the great "Decisive Battle" in mind, and built in 1932 by Mitsubishi's shipyard in Nagasaki.
Chōkai participated in numerous actions during the Pacific War including the Battle of Savo Island off Guadalcanal, in which she, along with other Japanese cruisers, sank the heavy cruisers , and . She was sunk in the Battle off Samar in October 1944.
Design
thumb|left|The bridge of Chōkai
The Takao-class cruisers were an improved version of the previous design, incorporating technical elements learned with the development of the experimental light cruiser . They had a distinctive profile with a large, raked main smokestack, and a smaller, straight, second smokestack. Intended to address issues with the Myōkō class, the Takao class had thicker armor, dual-purpose main guns which could be used against aircraft, and torpedo launchers moved to the upper deck for greater safety. However, as with its predecessors, the Takao class was also top-heavy.
The Takao class displaced . Chōkai was long, with a beam of , draft of and was capable of 35.25 knots. Following that, Chōkai pounded the heavy cruiser , and as Aoba, Kako, and Kinugasa joined in, Astoria sank. Finally, while other cruisers lit the cruiser aflame and sank her, Chōkai sank the heavy cruiser with two hits from her long lance torpedoes. 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. However, Chōkai sustained several hits from Quincy and Astoria, disabling her "A" turret and killing 34 men. Chōkai returned to Rabaul for temporary repairs. 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.
Subsequent action
Relieved as the Eighth Fleet flagship shortly after the final evacuation of Guadalcanal, Chōkai headed back to Yokosuka on 20 February 1943. Tasked with various minor duties for the remainder of 1943 and first half of 1944, Chōkai was made the flagship of the Cruiser Division Four ("CruDiv 4") comprising , , , and Chōkai on 3 August 1944. All four ships took part in the Battle of the Philippine Sea.
Battle of Leyte Gulf
thumb|Chōkai at anchor at [[Chuuk Lagoon|Truk, 20 November 1942. Battleship Yamato can be seen in the left background]]
CruDiv 4 was part of Admiral Takeo Kurita's large fleet of IJN battleships, cruisers, and destroyers that took part in the various engagements of the Battle of Leyte Gulf at the Philippines.
CruDiv 4 suffered a harrowing submarine attack on 23 October 1944, with the sinking of and (which was Kurita's flagship, though he survived), while was left permanently crippled, leaving Chōkai as the only undamaged ship of CruDiv 4.
Chōkai was then transferred to Cruiser Division Five, where she survived an air attack on 24 October 1944, while the battleship Musashi was sunk.
Sunk in the battle off Samar
On the morning of 25 October, Chōkai engaged an American force of escort carriers, destroyers, and destroyer escorts in the Battle off Samar. During her approach to the US escort carriers, Chōkai was hit several times on the port side amidships by 5"/38 caliber guns of this force's escort carriers and destroyers. It was believed at the time that one of these hits may have set off the eight deck-mounted Japanese Type 93 "Long Lance" torpedoes; however, 's expedition in 2019 found Chōkais torpedoes still intact. 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. Fires began to rage and she went dead in the water. She was scuttled later that day by torpedoes from the destroyer (), which also rescued some of her crew. Two days later Fujinami was sunk with the loss of all hands, including the Chōkai survivors.
Wreck
Chōkai sits upright in of water on the edge of the Philippine Deep. RV Petrel discovered the wreck of Chōkai on 5 May 2019 and dived it via ROV on 30 May 2019.