Page 24 - Unit 731

In 1938, Unit 731 forced a large number of Chinese labourers and drafted many ‘special construction workers’ from Japan to accelerate the construction of
the Pingfang Special Military Zone, where Unit 731 had gradually transferred after construction finished. The original headquarters of the Kamo Unit was
preserved as the office of Division Three of Unit 731, also known as the Epidemic Prevention and Water Purification Division. From this time on, the
largest scale bacteriological warfare research base in human history was built.
The Unit 731 base and many secret experiment laboratories were located along the Rafa–Harbin Railway connecting Harbin and Chengchun via
Xiangfang, Xuanjia, Pingfang, Jioujia, Nyujia, Ralin, Beiyinhe, and Anjia stations. The Japanese military implemented control by setting up secret zones
between Xuanjia, Pingfang, and Jioujia stations on the Rafa–Harbin Railway. Every train passing through Pingfang station was required to lower window
shades in advance, and passengers were forbidden to look outside. Anyone violating the rules would be arrested by Japanese officials and taken to the
Police Bureau or Kempeitai under suspicion. The zone seemed to be a city inside a city.
The secret military zone set up along the Rafa–Harbin Railway was commonly called ‘60 miles of national boundary’ (60 Chinese miles, or Li, is
equivalent to 30,000 metres). A branch line of the Rafa–Harbin Railway passed through Unit 731’s core area of bacteriological research, which exclusively
served Unit 731 to transfer ‘materials of human experiments’ as well as military materials and experimental devices.
Tiny Harbin, Large Pingfang

Facilities of Unit 731 were completed in August 1939, including the general office, Sifanglou (a special prison in the bacteriological research field),
experiment facilities, and infrastructure to supply heat, electricity, and water, as well as the exclusive railway and an airport. Additional facilities, such as
dormitories, material warehouses, Tōgō Shrine, Tōgō School, Tōgō Square, hospitals, halls, pubs, and sport fields, were also included. The total surface
area of Unit 731 core area was approximately 6.1 km square, and a wall 5,000 metres long, 2.5 metres tall, and 1 metre wide surrounded the general office
on which high voltage electric webs were installed. Trenches 3 metres wide and deep were dug outside the wall.
Unit 731 resembled a mysterious castle surrounded by military facilities—a high wall, electrical webs, and trenches. Pingfang Special Military Zone
was a no-fly zone; even flights of Japanese military were forbidden over the zone, and Unit 731 could shoot them down without advance authorisation. In
addition, the Consulate-General of Japan in Harbin and secret connecting points, such as the Jilin Street connecting point, were situated in downtown
Harbin outside the head office in Pingfang.
Covertly established by the Japanese Army, and applying biology and medicine in weapon research and manufacturing, Unit 731 conducted inhumane
activities in the isolated castle. As Unit 731 became more secretive and its scale grew larger, the rumour of ‘tiny Harbin, large Pingfang’ spread.

Epidemic Prevention and Water Purification Department
The Ishii Unit formally decreed the use of the name ‘Epidemic Prevention and Water Purification Department of the Kwantung Army’. In 1941, the Ishii
Unit and other divisions were generally called ‘Unit 659 in Manchuria’; the head office in Pingfang, ‘Unit 731 in Manchuria’; the Mudanjiang Detachment,
‘Unit 643 in Manchuria’; the Sunwu Detachment, ‘Unit 673 in Manchuria’; the Linkou Detachment, ‘Unit 162 in Manchuria’; the Hailar Detachment,
‘Unit 543 in Manchuria’; and the Dalian Research Institute of Health, ‘Unit 319 in Manchuria’.
Vast Organisational Structure

The organisation of Unit 731 was huge and consisted of a large number of personnel serving eight departments: General Affairs, Bacteriological
Experiments, Bacteriological Research, Epidemic Prevention and Water Purification, Bacteria Production, Training and Education, Equipment Supply, and
Therapy.
Apart from these eight departments, there was a special section responsible for prison management. Divisions were set up under each department,
sections were created under each division, and each section was named after the person in charge. The General Affairs Department was responsible for
writing plans of bacteriological warfare research, drafting unit commands, and personnel, backup, and finance, as well as labour management. The
Bacteriological Research Department, as the core institute of bacteriological research in Unit 731, was responsible for researching medicine for offensive
bacteriological warfare and producing serum and related defensive equipment. The Bacteriological Experiment Department studied the efficiency of
bacteriological weapons and attack methods against humans, animals, and plants. With manufacturing factories for water filters and shells used for
bacteriological bombs, the Epidemic Prevention and Water Purification Department was responsible for the epidemic prevention and water purification for
Unit 731, and studying and producing bacteriological bombs. Bacteria Production Department developed bacteria, studied and manufactured vaccines, and
produced bacteriological weapons. The Training and Education Department trained personnel in bacteriological research, manufacture, and usage, and
initiated education of epidemic prevention studies and bacteriological studies. The Equipment Supply Department was responsible for supplying
manufacturing equipment, preserving experiment equipment, bacteria, vaccines, and delivering animals for experiment. The Therapy Department provided
epidemic preventive methods and medical treatments for members of Unit 731 and their relatives.
On 2 December 1940, Yoshijirō Umezu, commander-in-chief of the Kwantung Army, signed the No. A398 combat command of the Kwantung Army:
‘… order the Chairperson of the Epidemic Prevention and Water Purification Department of the Kwantung Army to present arrangements of the following
units at designated locations: Mudanjiang Detachment—Hailin; Linkou Detachment—Linkou; Sunwu Detachment—Sunwu; Hailar Detachment—
Hailar’. 17
Unit 731 set up the Hailar Detachment, Mudanjiang Detachment, Linkou Detachment, and Sunwu Detachment in accordance with this command. In
addition, along with the Dalian Research Institute of Health, which was taken over by Unit in 1938 and transformed as the branch of the Epidemic
Prevention and Water Purification Department of the Kwantung Army in Dalian, and a Special Experimental Field and Chengzigou Experimental Field,
Unit 731 was comprised of large-scale bacteriological warfare research, production, and testing systems, all provided with vast personnel and
comprehensive facilities.
According to the Japanese records of ‘Name List of the Epidemic Prevention and Water Purification Department of the Kwantung Army’ (関東軍防疫
給水部留守名簿), in June 1945, there were four identities, namely general or colonel, officers, soldiers, and dependents. At that time, the Unit had 3,507
members total, including one lieutenant-general, one major-general, seven colonels, four lieutenant-colonels, thirty-five majors, fifty technicians, 135
assistant technicians, thirty-two captains, twenty-three first-lieutenants, twenty-six second-lieutenants, and nineteen chief warrant officers. 18
Expansion and Spread
The code of the Epidemic Prevention and Water Purification Department of the Kwantung Army was ‘731’. In reality, this department was one of eight
departments of the Kwantung Army responsible for studying water filtration and researching and producing defensive bacteriological warfare equipment.
Initiating a large-scale human experiment, Unit 731 prepared and executed bacteriological warfare under the name of ‘epidemic prevention and water
purification’. Other Epidemic Prevention and Water Purification Departments across Japan and Japan’s colonies imitated Unit 731 by claiming themselves
‘epidemic prevention and water purification’ to prepare and execute bacteriological warfare and human experiments.
According to records from the Ministry of Health, Labour and Welfare, a series of institutions related to bacteriological warfare was founded under