Question: Masaji Kitano was what rank when Unit 731 carried out the most notorious war crimes in Manchukuo?

Context paragraphs:
War crimes in Manchukuo: War crimes in Manchukuo were committed during the rule of the Empire of Japan in northeast China, either directly, or through its puppet state of Manchukuo, from 1931 to 1945.  Various war crimes have been alleged, but have received comparatively little historical attention.

Masaji Kitano: Masaji Kitano (北野政次 July 14, 1894 – May 17, 1986) was a medical doctor, microbiologist and the lieutenant general of the Imperial Japanese Army.  He was the second commander of Unit 731, a covert biological and chemical warfare research and development unit responsible for some of the most notorious war crimes carried out by Japanese personnel.

Unit 731: Unit 731 (Japanese: 731部隊 , Hepburn: Nana-san-ichi Butai ) was a covert biological and chemical warfare research and development unit of the Imperial Japanese Army that undertook lethal human experimentation during the Second Sino-Japanese War (1937–1945) of World War II.  It was responsible for some of the most notorious war crimes carried out by Japan.  Unit 731 was based at the Pingfang district of Harbin, the largest city in the Japanese puppet state of Manchukuo (now Northeast China).

American cover-up of Japanese war crimes: The American cover-up of Japanese war crimes occurred after the end of World War II, when the occupying US government granted political immunity to military personnel who had engaged in human experimentation and other crimes against humanity, predominantly in mainland China.  The pardon of Japanese war criminals, among whom were Unit 731's commanding officers General Shiro Ishii and General Masaji Kitano, was overseen by General of the Army Douglas MacArthur in September 1945.  While a series of war tribunals and trials was organized, many of the high-ranking officials and doctors who devised and respectively performed the experiments were pardoned and never brought to justice.  As many as 12,000 people, most of them Chinese, died in Unit 731 alone and many more died in other facilities, such as Unit 100 and in field experiments throughout Manchuria.

Abwehrgruppe 218: Abwehrgruppe 218, known under the codename "Edelweiss" (German: ""Edelweiß"" ) was an Nazi German anti-partisan unit operating in Slovakia during World War II.  Unit was constituted during September 1944 and led by SS-Sturmbannführer Erwein von Thun-Hohenstein.  In the period from September 1944 to April 1945 the unit carried out more than 50 missions, which resulted in killing around 300 people, including civilians; another 600 were taken prisoner.  One of the most famous actions of the unit was the capture of members of an American OSS mission under command of Lieutenant James Holt Greene and a British SOE mission under Major John Sehmer on 26 December 1944 in the Nízke Tatry Mountains.  The unit is known for a number of war crimes, especially the massacre of civilians in the villages of Ostrý Grúň and Kľak, among the most notorious war crimes committed on Slovak territory during the war.

Battle casualties of World War II: The article summarizes casualties in different theatres of World War II in Europe and North Africa.  Only the military losses and civilian losses directly associated with hostilities are included into the article.  The actions of the Axis' and Allied military or civilian authorities that fit the definition of genocide, or war crimes (including Nazi war crimes, Soviet war crimes, Allied war crimes, Holocaust, Nazi crimes against Soviet POWs "et caetera") are left beyond the scope of the present article.

Zhongma Fortress: Zhongma Fortress — or Zhong Ma Prison Camp, or Unit Tōgō — was a prison camp where the Japanese Kwantung Army carried out covert biological warfare research on human test subjects.  Built in Beiyinhe, outside of Harbin, Manchukuo during the Second Sino-Japanese War, the camp served as a center for human subject experimentation and could hold up to 1,000 prisoners at any given time.  In 1937 the prison camp was destroyed and testing operations were transferred to Pingfang under Unit 731.

The Wehrmacht War Crimes Bureau, 1939-1945: The Wehrmacht War Crimes Bureau, 1939-1945 is a book by Alfred-Maurice de Zayas.  It was published in November 1979 in Germany by Universitas/Langen Müller under the title "Die Wehrmacht-Untersuchungsstelle", and in America in 1989 under the title "The Wehrmacht War Crimes Bureau, 1939-1945" (University of Nebraska Press).  Professor Howard S. Levie, an expert in international humanitarian law, provided the preface for the American version.  The book describes some of the work of the Wehrmacht War Crimes Bureau, a special section of the legal department of the Wehrmacht High Command, which collected reports of alleged Allied and German war crimes for purposes of diplomatic protests, war crimes trials, and white books.

James Gowing Godwin: James Gowing Godwin (12 March 1923–2 May 1995) was a Royal New Zealand Navy aviator, prisoner of war, war crimes investigator and colonial administrator.  After the end of World War II, as a captain in the Australian Army he became an investigator with the Second Australian War Crimes Section in Tokyo in July 1947; he developed the case against Lieutenant General Takuma Nishimura for ordering the mass execution and cremation of 155 wounded Australian and Indian soldiers at war crimes at the Parit Sulong Massacre.  He also worked for the First Australian War Crimes Section, based in Singapore, then worked for the British colonial service.

Yasuji Kaneko: Yasuji Kaneko (金子 安次 , Kaneko Yasuji , January 28, 1920 – November 25, 2010) was an ex-soldier of the Imperial Japanese Army, and a former detainee of both Siberian Internment by the Soviet Union during 1945–1950 and Fushun War Criminals Management Centre in China during 1950–1956.  He was known for his extensive war crimes testimony, including his alleged involvement in the Unit 731.  His testimony appeared in the 2001 film "Japanese Devils" and the 2007 film "Iris Chang: The Rape of Nanking" (although he was not involved in the Nanking Massacre).  He was a member of the Association of Returnees from China.

Supporting paragraphs: Masaji Kitano Unit 731
Answer: second commander