d Soviet tanks On 6 July 1938, the Japanese
Kwantung Army decoded a message sent by the Soviet commander in the
Posyet region to Soviet
headquarters in
Khabarovsk. The message recommended that Soviet soldiers be allowed to secure unoccupied high ground west of
Lake Khasan, most notably the disputed Changkufeng Heights, because it would be advantageous for the Soviets to occupy terrain which overlooked the Korean port-city of
Rajin, as well as strategic railways linking Korea to Manchuria. In the next two weeks, small groups of Soviet border troops moved into the area and began fortifying the mountain with emplacements, observation trenches, entanglements and communication facilities. On 7 July, from
Posyet where the headquarters of the 59th border detachment was located, a request was made to allow the capture of the height, which was actually already occupied: the first deputy People's Commissar of Internal Affairs of the USSR,
Mikhail Frinovsky, needed to file a document coming from his subordinates to the superior command. According to commander
Grigory Shtern, chief of staff of the
Far Eastern Front, on 8 July, "by decision of the commander of the 59th border guard detachment, the height was occupied and one heavy machine gun was set up." There can be no question of any initiative by the head of the border detachment: the order was personally given by Frinovsky but this was done orally. In writing, everything was formalized as a request from Colonel
Kuzma Grebennik, commander of the 59th Border Detachment, who wrote that "The Japanese are preparing to capture the height with a horizontal mark of 100, they are laying a telephone line, they have reached the western slopes of this height ... They can preempt the capture". Colonel Fedotov's order from the Far Eastern Border Forces headquarters immediately followed: to guard the height with a permanent outfit. And already by order of the head of the Posietsky border detachment, the
Zaozernaya Hill was first captured by a permanent detachment (10 people), and then a reserve outpost approached with another 30 fighters. On the night of 8–9 July 1938, the Soviet border guards, following the order of the command, began to install barbed wire and dig trenches. On 10 July 1938, the deputy head of the Posyetsky border detachment, Major Alexander Alekseev, reported to the military headquarters in
Khabarovsk that the height is engaged in a reserve outpost, in addition to the outposts Podgornaya and Pakshekori. The conflict started on 15 July, when the Japanese
attaché in
Moscow demanded the removal of Soviet border troops from the
Bezymyannaya (сопка Безымянная, Chinese name: Shācǎofēng = 沙草峰) and
Zaozyornaya (сопка Заозёрная, Chinese name: Zhāng Gǔfēng = 张鼓峰 (Changkufeng)) Hills to the west of Lake Khasan in the south of
Primorye not far from
Vladivostok, claiming this territory by the
Soviet–Korea border. The Soviets were performing trench works and built rock heaps and laid several land mines on slopes of the hill, not only on the Soviet slope of the hill, but also on Manchurian territory. The Japanese embassy protested, demanding that the status quo will be restored, but the Soviet government denied those accusations. On 15 July, Colonel Grebennik reported that the readiness of trench work was 80%; barriers were 50%; and that three cell trenches had been opened in full profiles, each for one compartment. Meanwhile, Frinovsky’s special group reached the headquarters of the 59th Posyet border detachment, from where they moved to the Zaozernaya hill. The formal pretext for an official of such a high rank (the second person in the NKVD) to go to the very border line was the same “investigation” of Lyushkov’s escape. To accompany this retinue, Lieutenant Vinevitin was assigned as a sniper. At first, the
Japanese Korean Army, which had been assigned to defend the area, disregarded the Soviet advance. However, the Kwantung Army, whose administrative jurisdiction overlapped Zhāng Gǔfēng (Changkufeng), pushed the Korean Army to take more action, because it was suspicious of Soviet intentions. Following this, the Korean Army took the matter to Tokyo, recommending that a formal protest be sent to the Soviet Union. Frinovsky’s retinue, which included Lieutenant
Vasily Vinevitin, appeared on
Zaozernaya Hill on 15 July. Then, as follows from the documents, something completely unexpected happened: on Frinovsky’s orders, several people from his retinue crossed the border line and, entering Manchurian territory, demonstratively began to pretend to be carrying out engineering and earthworks there. The "Japanese-Manchus" noticed this and sent a small group to the site of the violation. Before reaching the border, the gendarmes politely asked the Soviets to stop its perceived illegal work on Manchurian territory. Lieutenant Vinevitin, with a well-aimed rifle shot to the head, killed the persistent Japanese on the spot – on the personal order of Frinovsky. ==Battle==