The I-68 (later I-168) was a Japanese submarine whose keel was laid in 1931, launched in June 1933, and commissioned in the Imperial Japanese Navy in 1934. The length of the ship at the time of launching was 98 m, width 8.2 m, and the underwater displacement - 2,440 tons. The maximum surface speed of the I-68 reached 23 knots on the surface. The main armament was six 533 mm torpedo launchers, and the secondary armament was a single 120 mm gun and one 13.2 mm anti-aircraft machine gun.
The I-68 was a submarine of the Kaidai type (subtype: KD6A), developed on the basis of the experience gained during the operation of ships of the KD5 subtype. Compared to them, it had a slightly higher underwater displacement and slightly changed additional armament. However, it had a clearly higher surface speed. At the outbreak of World War II in the Pacific, he was operating in the Hawaii area, taking part in the Japanese attack on the base at Pearl Harbor on December 7, 1941. While carrying out the tasks he was assigned, he was damaged, which led to his directed to Kwajalein for minor repairs. In May 1942, the ship changed her designation from I-68 to I-168. The ship, already as the I-168, took part in the Battle of Midway in June 1942 with great success, when it sank the American destroyer USS Hammann and finished off the USS Yorktown aircraft carrier. After the Battle of Midway, the ship was sent for repairs to Japan, and in the second half of 1942 and in early 1943, she served in the Solomon Islands, and later in the Aleutian Islands. Ship I-168 was sunk on July 27, 1943 in the Rabaul area by the USS Scamp.