The 'Seishin Landing Operation' was a Soviet amphibious assault on the Japanese forces in the northern part of Korea (13/17 August 1945).

The operation was carried out by elements of the Soviet Northern Pacific Flotilla of Admiral Ivan S. Yumashev’s Pacific Fleet and targeted the Ranam-guyok Military District in the last days of World War II.

During the Soviet 'Avgust Buri' invasion of Manchuria in August 1945, the 1^st Far Eastern Front, under the command of Marshal Sovetskogo Soyuza Kirill A. Meretskov, was the easternmost of the three Soviet army groups committed to the offensive, and advanced to the south along the coast of northern Korea. As part of this effort, it was decided to conduct three amphibious landings in the rear of General Otozo Yamada’s Japanese Kwantung Army.

Between 11 and 13 August, the first two landings by the Pacific Fleet were executed to seize the ports of Yuki (now Sonbong) and Racine (now Rason) on the north-east coast of Korea, and these encountered some limited resistance only in Racine.

Encouraged by these initial success, Yumashev ordered the launch of the next amphibious assault on the port of Seishin (now Chongjin). The two previous ports had been only lightly defended, but Seishin was well fortified and had a strong Japanese garrison totalling some 4,000 men reinforced by retreating units of Lieutenant General Keisaku Murakami’s 3^rd Army of the Kwantung Army.

In view of the successful development of the 1^st Far Eastern Front’s offensive, on 12 August Meretskov cancelled the previously scheduled landing at Seishin. However, the fleet command continued preparations for the landing, hoping for an easy success. Yumashev managed to get permission to conduct the operation from the Marshal Sovetskogo Soyuza Aleksandr M. Vasilevsky, commander-in-chief of the Soviet troops in the Far East. Given Meretskov’s earlier decision to cancel the operation, however, the fleet did not receive the infantry division previously planned for the landing in Seishin, and Yumashev was forced to go ahead with a limited number of troops in the form of the 140^th Reconnaissance Detachment, the 13^th Marine Brigade, the 355^th Marine Battalion and the 62^nd Machine Gun Battalion.

To compensate for the limited size of his landing force, Yumashev ordered a series of powerful pre-operation attacks by his air and torpedo boat elements, the former attacking the port on a daily basis between 9 and 13 August. Even so, the undertaking’s overall plan remained unchanged: the preliminary landing of a reconnaissance group, and then the build-up of the landing force’s strength.

As noted above, since 9 August continuous air attacks had hit Seishin, in whose port, according to the Soviets, about 10 Japanese ships were sunk. On 12 August, some Soviet ships entered the harbour and established the fact that there were no Japanese warships present. As a result, it was decided to start the operation without waiting for the final completion of the battle for Racine and the redeployment of the fleet’s light forces from there. Thus the operation’s launch point remained Vladivostok and, being significantly farther from Seishin, this immediately deprived the Soviet command of the ability to make any rapid response to a changing situation.

The Soviet force comprised one destroyer, one minelayer, eight patrol ships, seven minesweepers, two small submarine chasers, 18 motor torpedo boats, 12 landing ships and seven transport vessels. For air support, 261 aircraft (188 bombers and 73 fighters) were allocated, and the commander of the naval forces was Kapitan 1-go ránga A. F. Studenichnikov, and the commander of the landing force was Generalmajor Vasili P. Trushin, commander of the 13^th Guards Naval Infantry Brigade, under Yumashev’s overall supervision.

In the Seishin area, the Japanese had one infantry battalion, the men of the local officer’s school, and the sailors of the city’s naval base, reinforced during the operation by the retreating units of the Kwantung Army's 3^rd Army: these strengthenings were firstly two infantry regiments, then the Guards Division. The Japanese troops were led in the battle by the commander of the Ranan Divisional District, Lieutenant General Munekichi Nishiwaki.

During the afternoon of 13 August 10 motor torpedo boats entered the port of Seishin and landed the 140^th Reconnaissance Detachment of the Pacific Fleet headquarters under the command of Lieutenant Viktor Leonov and one company of sub-machine gunners of the 13^th Naval Infantry Brigade. Totalling 181 men under the command of Polkovnik A. Z. Denisin, the landed force entered the city as the Pacific Fleet’s vessels, less two boats to provide cover from the sea, returned to Vladivostok.

The assault force easily occupied the port and the surrounding urban areas, taking advantage of the Japanese force’s complete surprise. However, the Japanese soon launched a counterattack, at first disorderly and fragmented. The Japanese command quickly restored order and launched an better organised offensive against the landing force, and the situation of the 140^th Reconnaissance Detachment immediately deteriorated: it was cut off from the coast in an unfamiliar city and the Japanese also succeeded in cutting the detachment in two. By 18.30, seven more motor torpedo boats had arrived to land 90 more men (one machine gun company) in an area not immediately associated with the battlefield. This unit could not break through to join the 140^th Reconnaissance Detachment, suffered heavy losses and was forced onto the defensive. Thus, the Soviet landing force’s situation became critical, and the Soviet troops were threatened with annihilation.

By the end of the day, the fleet commander had despatched an EK-2 guardship and two minesweepers from Vladivostok with the 355^th Marine Battalion, but these vessels could reach Seishin only on the following day. Another major flaw on the Soviet tactical thinking was also revealed: no observers had been included in the landing force, so the naval warplanes had to strike at a distance from the battlefield to avoid bombing their own troops, so direct air support for the landing force was totally absent. During the night, the reconnaissance detachment fought an extremely fierce battle in three separate groups, beating off continuous counterattacks and soon running short of ammunition.

On the morning of 14 August, the reinforcement convoy reached Seishin and landed the 355^th Marine Battalion of 710 men under the command of Major M. P. Barabolko, who led his troops into the city and advanced some 0.6 to 1.85 miles (1 to 3 km). However, by introducing fresh forces into battle and supporting its ground forces with the artillery fire of an armoured train, by the night of 14 August the Japanese had driven the Soviets back to the port, where they held a beach-head of 1.25 miles (2 km) wide and 0.6 mile (1 km) deep. It was only part of the battalion which led the defensive fight in the area of the port’s piers, while several more groups were cut off from their unit and fought separately in some of the city’s high-rise buildings. In addition, for lack of any accurate information about the situation on the ground, the battalion had been landed too far away from the three advanced landing groups in the city and therefore could not link with them.

The tactical situation therefore remained critical. A volunteer detachment of 25 men under the command of Kapitan 3-go ránga G. V. Ternovsky was hastily formed from the crews of the ships and came ashore. During the night, the Soviets had to repel 14 Japanese attacks, and it was only as a result of their courage and high degree of combat training that the marines managed to survive. The ships that arrived in the morning remained in the harbour and gave the troops ashore gunfire support. As a result of the day’s poor weather on that day, the use of Soviet air power was impossible, only two bombers reaching Seishin and having little effect. The main detachment of 23 ships departed Vladivostok with the 13^th Marine Brigade, and during the night the elderly destroyer Voikov and a tank landing barge with seven T-26 light tanks sailed for Seishin.

At about 04.00 on 15 August, the ships entered the port of Seishin and the main strength of the 5,000-man landing force began to disembark in the Soviet beach-head under heavy Japanese fire. The resistance of an ever-increasing adversary was so powerful that the launch of an entire brigade into battle did not immediately produce a turning point in the battle. Only in the middle of the day, with the aid of tanks and naval gunfire support which damaged the Japanese armoured train and forced its retirement, was the port finally cleared and the fighting to take the city begun. By the evening, the city had been almost completely cleared of the Japanese, saving the survivors of the Soviets' initial landing forces. Stubborn fighting continued in the outskirts of the city, and General Leytenant Sergei I. Kabanov arrived to assume leadership of the operation.

In the afternoon, another detachment of ships (one destroyer, two minesweepers, three transport vessels, one patrol board and and one border boat) departed Vladivostok carrying the third echelon of the assault forces: 615 soldiers, 60 guns and mortars, and 94 vehicles. Almost all the ships remained in the harbour and supported the offensive with artillery fire. The Japanese tried to counteract the weight of the Soviet firepower with the fire of their surviving coastal artillery and with attacks of individual aircraft. In the harbour a minesweeper was damaged by a US naval mine.

On 16 August, the landing force’s third echelon was landed in the port, while two more minesweepers were significantly damaged by mines. The fleet command, realising that it had underestimated the Japanese, was now building up the strength of the landing force. At first, another tank landing barge with seven T-26 tanks and two vehicles aboard was sent to Seishin. Then, the next detachment of ships, not initially planned, left Vladivostok as one patrol ship, one minesweeper, six landing craft and one tank landing ship carrying the 205^th Regiment and military equipment. During the day, the landing forces executed a limited offensive from Seishin towards the north and north-west.

At this time the Japanese troops in the area of the city received a message about Emperor Hirohito’s order for the surrender of Japan, and although a number of units refused to lay down their arms, organised resistance had almost ceased by the end of the day. In some areas, the surrender of Japanese soldiers began.

On 17 August, the ships which had departed Vladivostok on the previous day arrived at the port and the landing of the troops was carried out safely. There were small skirmishes with individual Japanese groups. Most of the Japanese were taken prisoner, but some of their units left the front and tried to move to the south.

At about 11.30, a forward detachment of the 25^th Army under the command of General Polkovnik Ivan M. Chistyakov of the 1^st Far Eastern Front reached the positions of the landing force, and the 'Seishin Landing Operation' was at an end.