"Yamashita was the son of a physician, who started the child in a military career. At the military academy he was a year junior to his lifetime rival, Hideki Tojo, and graduated at the head of his class."  Tojo, however, became suspicious of him.
By 1932, when only 47, he became section chief of military affairs in the War Ministry and was earmarked as an eventual war minister or even premier. He was also a member of the Issekikai, an informal association of staff officers who believed in a military solution to the problems of Manchuria and Mongolia. 
While "Young Officers" of the Imperial Way Faction carried out the February 26, 1936 Incident, Yamashita was not thought complicit, but still was under enough suspicion to have him transferred to Korea. He had had prior knowledge of the plot but did nothing, although during the coup attempt, he acted as a go-between between the rebels and the palace. Harris & Harris wrote that the resulting anger of Emperor Hirohito, when Yamashita was sympathetic to the rebel demands, hurt his career,  although Bergamini calls him a Palace underground agent.
Tojo transferred him to an isolated brigade command in Korea. According to his wife, he was considering retirement, and began looking for civilian employment, when his Palace contact, former Aide-de-Camp Bunzabaro Kwagashi, brought him a "personal note of encouragement and appreciation from Hirohito."
When, however, the Second Sino-Japanese War broke out, he distinguished himself, was promoted, and give command of North Korea. Tojo, who now led the Control Faction, again was concerned about Yamashita's popularity, and transferred him to an isolated post in Manchuria.
Yamashita was placed in charge of the 25th Army and took Singapore by a surprise attack through Malaya. His troops were noted for adaptability and personal preparation, , in strong contrast to the British defenders, who regarded Malaya as impenetrable jungle. The British Jitra Line, expected to last six months, fell in three days. As Japanese morale increased and British morale fell, the attack turned into a race rather than a deliberate operation.
Before and during the final attacks, Yamashita visually observed the front from an observation towar in the palace of the Sultan of Johore. Yamashita inspired troops with the message "I, this whole day, pushing forward the command post to the heights of the Johore Imperial Palace, will observe directly the strenuous efforts of every divisional commander."
- Singapore Fortress was solid and strong facing the sea, but vulnerable on the peninsular side facing the Johore Strait;
- Newspaper reports of a strong Royal Air Force (RAF) presence were propaganda;
- Although British forces in Malaya numbered from five to six divisions (well over 80,000 men), less than half were Europeans.
Attached to Yamashita's 25th Army, Tsuji became known as the "God of Operations" or "God of Strategy". He planned the Sook Ching or Operation Clean Up incident.
Under the guise of preemptory attack against possible Chinese Communist guerillas, he drafted the orders to kill somewhere between 3,000 and 10,000 Chinese residents of Singapore. This fact clearly demonstrates he was both predisposed to and fully capable of initiating the most unspeakable of atrocities when he felt they suited his purposes. Even though the killing went on for nearly a month, Yamashita and his staff only learned of Tsuji’s actions well after the fact since the 25th army had been moved to Sumatra leaving only an occupation force in Singapore. 
Threat to Australia
In February 1942, after air raids on Darwin, Australia, Admiral Isoroku Yamamoto wanted to land a force of one or more divisions on the undefended Austrialian north coast, and Yamashita volunteered to lead them. Tojo, and others on the General Staff, however, were less enthusiastic, having no contingency plans, and having significant concerns about supplying the forece and maintaining air superiority. Hirohito decided that invading Australia was a lesser priority than invading Burma. .
There are different explanations of how he received the Philippines command. One is that a faction, originally sympathetic to the Strike-North Faction, who wanted to replace the Koiso Cabinet with a "war prosecution government" headed by Yamashita. In September 1944, members approached Prince Asaka and Prince Takeda, who took the matter to the Lord Privy Seal, Koichi Kido. Kido was not prepared to disrupt his plans for winding down the war, and made the alternative suggestion of reposting Yamashita to the Philippines. 
Another author wrote
General Tomoyuki Yamashita was a man at the wrong place at the wrong time.
When the Japanese regional commander, Field Marshal Hisaichi Terauchi, lost confidence in the Philippines area commander, expecting an invasion, he replaced him with Yamashita. There was little or no staff turnover, and the invasion began 11 days after he took command. "General Yamashita barely had time to put together a staff, learn the situation, and make basic defensive plans. He undoubtedly was not thinking about "law of war" training. 
Trial and death
One of the best-known cases involving command responsibility, the specific example of which being called the Yamashita Doctrine, refers to the 1945 prosecution and eventual execution of Gen. Yamashita. It is widely accepted that Yamashita ordered his troops not to participate in atrocities, but had poor communications with subordinate units. In at least one case, a senior subordinate commander, RADM Sanji Iwabuchi, "declined to obey" Yamashita's declaration of a Manila as an open city, refused to join Yamashita's main force in rural areas north of Manila, and massacred approximately 100,000 civilians.
Terauchi had a stroke on 10 April 1945, and surrendered to Lord Mountbatten on 12th September 1945, and died in November 1945; it is not known if he was to be charged as Yamashita's commander. Yamashita also had surrendered on 2 September, at Bagio, to the representatives of the Allied forces, among whom was Gen. Arthur Percival, whom he had defeated at Singapore.
At a tribunal in Manila, he was charged with not preventing war crimes by troops under his command, even though evidence was given that he tried to prevent them, and also had poor communications with subordinates. The Yamashita Doctrine requires that a commander, even though he does not take active part in atrocities, has a positive responsibility to prevent them. It has proven inconvenient in other wars, such as the possible command responsibility of Gen. William Westmoreland for the My Lai massacre, of which Westmoreland has never been suspected of having prior knowledge.
There have been questions if Douglas MacArthur exerted undue command influence over the title. It is worth noting that MacArthur granted Masaharu Homma, the Philippines commander in 1941-1942, the more "honorable" privilege of being shot, while he insisted Yamashita be hanged.
- Warwick L. Bennett, Tomoyuki "The Tiger of Malaya" Yamashita, FindAGrave
- Merion and Susie Harris (1991), Soldiers of the Sun: the Rise and Fall of the Imperial Japanese Army, Random House, p. 148
- Harris & Harris, p. 191
- David Bergamini (1971), Japan's Imperial Conspiracy, Morrow, p. 640
- Bergamini, pp. 658-659
- Harris & Harris, p. 305
- Harris & Harris, pp. 307-308
- Alan C. Headrick (8 February 1994), Bicycle Blitzkrieg: The Malayan Campaign and the Fall of Singapore, U.S. Naval War College
- Jim Nelson, The Causes of the Bataan Death March Revisited, U.S.-Japan Dialogue on POWs
- Bergamini, pp. 898-899
- Bergamini, p. 1017
- Bruce D. Landrum, The Yamashita War Crimes Trial: Command Responsibility Then and Now, Judge Advocate General Graduate Course
- Trial of General (United States Military Commission, Manila, Oct. 8-Dec. 7, 1945) IV Law Rep. Trials War Crim. 1 (UN War Crimes Comm'n, 1948); aff'd In re Yamashita 327 US 1 (1946).
- Laurie Barber (September 1998), "The Yamashita War Crimes Trial Revisited", WaiMilHist, Electronic Journal of Military History within the History Department at the University of Waikato, Hamilton NZ
- "The Nation: Of Guilt and Precedent", Time, 18 January 1971