Kō-hyōteki-class submarine

	Type A Ko-hyoteki-class submarine, No.19, grounded in the surf on Oʻahu after the attack on Pearl Harbor, December 1941
Class overview
Operators	Empire of Japan
Succeeded by	Kairyū-class submarine
Subclasses	Type 'A' ; Type 'B' ; Type 'C' ; Type 'D' Kōryū;
Planned	3 × prototypes; 51 × Type 'A' ; 0 × Type 'B' ; 47 × Type 'C' ; 496 x Type 'D' ;
Completed	216; 1 × First prototype; 2 × Second prototype; 46 × Type 'A' ; 5 × Type 'B' ; 47 × Type 'C' ; 115 x Type 'D' ;
General characteristics (Type A)
Type	midget submarine
Displacement	46 long tons (47 t) submerged
Length	23.9 m (78 ft 5 in)
Beam	1.8 m (5 ft 11 in)
Height	3 m (9 ft 10 in)
Propulsion	192 trays of two two-volt cells each,; 136 trays forward; 56 trays aft; 1 × electric motor, 600 hp (447 kW) at 1800 rpm; 2 × screws counter-rotating on single shaft; leading prop 1.35 m diameter, right-handed;; trailing prop 1.25 m diameter, left-handed;
Speed	23 knots (43 km/h; 26 mph) surfaced; 19 knots (35 km/h; 22 mph) submerged;
Range	100 nmi (190 km) at 2 kn (3.7 km/h; 2.3 mph); 80 nmi (150 km) at 6 kn (11 km/h; 6.9 mph); 18 nmi (33 km) at 19 kn (35 km/h; 22 mph);
Test depth	30 m (98 ft)
Complement	2
Armament	2 × 450 mm (17.7 in) torpedoes, muzzle-loaded into tubes; 1 × 140 kg (300 lb) scuttling charge;
Notes	Ballast: 2,670 kg (5,890 lb) in 534 × 5 kg lead bars

The Kō-hyōteki (甲標的, Kō-hyōteki; Target 'A') class was a class of Japanese midget submarines used during World War II. They had hull numbers but no names. For simplicity, they are most often referred to by the hull number of the mother submarine. Thus, the midget carried by I-16-class submarine was known as I-16's boat, or "I-16tou".

This class was divided in four types: Type A Kō-hyōteki (甲標的甲型, Kō-hyōteki kō-gata; Target 'A', Type 'A'), Type B Kō-hyōteki (甲標的乙型, Kō-hyōteki otsu-gata; Target 'A', Type 'B'), Type C Kō-hyōteki (甲標的丙型, Kō-hyōteki hei-gata; Target 'A', Type 'C'), and Type D Kō-hyōteki (甲標的丁型, Kō-hyōteki tei-gata; Target 'A', Type 'D'), the last one better known as Kōryū (蛟龍).