The 1928 assassination of a Chinese warlord that set Japan on the path to war in China is being seen in a new light with the recent release of a biography of the Japanese officer who masterminded the incident.

The book titled “‘Cho Sakurin o Koroshita Otoko’ no Jitsuzo” (A real image of ‘the man who killed Zhang Zuolin’) runs to 534 pages and was published by Bungeishunju Ltd. in late August. It retails for 1,500 yen ($13.69).

It was penned by Fumiko Kuwata, 82, the granddaughter of Col. Daisaku Komoto (1883-1953), who engineered the explosion in northeastern China that killed Zhang as his train was traveling east of the Huanggutun district in the suburb of Mukden (present-day Shenyang). The date was June 4, 1928.

The furor that resulted in the aftermath of the Huanggutun Incident galvanized the militarism.

The work features letters to Komoto, a former staff officer of the Kwantung Army, from senior Imperial Japanese Army officers after he was booted out in disgrace.

Born in Dalian, China, Kuwata lived with Komoto as a child.

She started exploring Komoto's war exploits after she was invited to a symposium to mark the 80th anniversary of the assassination in 2008.

Zhang was one of the most powerful warlords at the time as he had seized control of Manchuria in northeastern China.

Although the Cabinet of Prime Minister Giichi Tanaka (1864-1929) pledged to Emperor Hirohito, posthumously known as Emperor Showa, that it would punish the perpetrator severely, the government bowed to pressure from the Army and simply suspended Komoto from duty on grounds of lax security.

The decision drew the wrath of Hirohito, leading to the resignation of all Cabinet members on July 2 the following year. After the incident, the Army strengthened its hold over the government and its policies.

Kuwata wrote that letters from top military brass proved essential in putting the biography together. The letters were sent to Komoto around July 1930 after he was dismissed from the Army, and were given to Kuwata by her aunt who died in 2011.

A letter by Chotaro Muraoka (1871-1930), who served as commander of the Kwantung Army at the time, was dated June 28 of that year. The letter written on “washi” traditional paper with a brush said Komoto had been treated “disgracefully.”

“I am solely to blame for the outcome,” Muraoka stated by way of apology.

Ten or so other senior officers also sent letters of comfort and encouragement to Komoto.

It was extremely rare for generals, lieutenant generals and others of high rank to express such sentiments one after another as Komoto was merely a colonel in the Kwantung Army, a subordinate body to the Imperial Japanese Army.

Theories abound on the background and motivation for the incident, but Kuwata concluded from the letters that the assassination reflected the intentions of leading members of the Imperial Japanese Army.

Takashi Ito, professor emeritus of Japan’s modern political history at the University of Tokyo, said after examining the letters there was no indication of a conspiracy between Komoto and core officers.

Nevertheless, he was surprised that senior officers “readily stood by Komoto.”

This led him to surmise that Komoto and others simply anticipated what they thought top Army officers wanted and went ahead. The notion is best expressed in Japanese as "sontaku."

The biography explains that Komoto spent many years in China after he was kicked out of the Army.

He moved to Manchuria in late 1931 at the request of an Army executive and became a director of South Manchuria Railway Co. He also held a number of other important positions while staying there.

In 1942, Komoto was asked by an Army buddy to visit China's Shanxi Province to oversee coal mining operations and negotiations with local warlords. Even after the end of World War II, he remained there.

After the Chinese Communist Party seized power in 1949, Komoto was held as a political prisoner. He died of illness while incarcerated in August 1953 at the age of 70.

“I keenly felt how an organization ultimately functions to protect only itself,” she said.

Kuwata said she learned something very important from finishing the biography: that people, such as her grandfather, act and think only in ways that reflect the times in which they live.

“For that very reason, the kind of education one receives during childhood is very important,” she said.