During World War 2 (1939-1945), the Imperial Japanese Navy (IJN), in a rather delayed endevvor, enacted an emergency shipbuilding program in 1943 to satisfy convoy escort / defense amidst mounting losses in the Pacific (particularly along the contested Dutch East Indies route. This led to the "Type C" Escort Ships being developed with the intention of fielding them in great numbers - haste was built into their production process which featured as little complication as possible for such was the desperation of the service to preserve what little resources it had left. Three-hundred Type C ships were planned but only fifty-six or so were completed before and after war's end (1945). Of those built, about 28-30 (sources vary) were lost to action while a further twenty-eight managed to see service to the final days of the war in August 1945 while, still others, went on to see post-war services with the likes of China/Taiwan and Russia for a time.
These escort ships had a modest displacement of 760 tons under standard loads and featured an overall length of 221 feet with a beam of 27.6 feet and a draught down to 10 feet - the latter quality giving them close-to-shore capabilities. Power was from 2 x Geared marine diesel engines developing 1,900 horsepower to 2 x Shafts under stern allowing for a maximum speed (in ideal conditions) of 16/16.5 knots with range out to 6,500 nautical miles. The crew complement numbered 136. Installed systems including the Type 22-Go radar, the Type 93 sonar, and the Type 3 hydrophone.
As built, the vessels were outfitted with 2 x 4.7" (120mm) /45 caliber Dual-Purpose (DP) turreted main guns, 6 x 25mm Type 96 Anti-Aircraft (AA) autocannons and 12 x Type 3 depth charge launchers (1 x Depth charge chute) with 120 x Depth charges carried. From 1944 onward, a single 81mm mortar was fitted on some ships. With this armament array, the Type C vessels could conceivably handle on-sea, undersea, and aerial threats while accompanying merchant forces to-and-from far-off Japanese holdings in the Pacific region.
Their design profiles included an unobstructed forecastle with a stepped-down hull line running cleanly to stern. A primary turret was fitted to the bow with good engagement angles and the bridge superstructure sat immediately aft. A main mast was fitted aft of the bridge section and the smoke funnels were installed near midships (ahead of the secondary mast works). Additional armament was fitted heading aft.
To ease large-scale production, the warships were designed as simply and as cleanly as possible so even more primitive Japanese shipyards could contribute to their manufacture to satisfy the numbers required - welded construction being used wherever possible. The class kept some of the qualities of earlier IJN escorts including the "endless-chain" depth charge system which facilitated the arming, loading, and discharging of depth charges at the stern. However, onboard systems were utilitarian which, in some cases, negated the vessel's forward-thinking measures.
Entering service in late-1943-1944, the Type C-class ships were typically assigned to IJN destroyer divisions but ended up as fodder for American submarines - the new design had good range but was inherently slow-moving with ultimately lacked much combat value for the changing fortunes of war. Such was the speed at which the service required the warships that the class featured no named vessels - only numbers - for identification purposes (ships Nos. 1 through 268 with gaps in between). Production issues inherent in the creation of the Type C ships inevitably led the IJN to invest in the related "Type D" vessels which were slightly faster at 17.5 knots but with less range despite the addition of fuel stores.