Human habitation of the Japanese archipelago dates back at least 35,000 years.
An imperial court centred on a hereditary emperor and influenced by Chinese political and social institutions reaches maturation at the start of the 8th Century. The emperor claims direct descent from the Japanese gods.
Over the next 400 years Japanese culture becomes increasingly sophisticated and cohesive. However, in the 12th Century the country enters a 400-year period of turmoil; a time characterised by disunity, civil war, feudalism, a decline in the power of the emperor and military control of government.
Late in the 16th Century the country begins to reunify under a stable but insular regime. While foreign trade is encouraged, Westerners are viewed with suspicion and only allowed restricted access to the mainland.
Intrusions by the West mount during the 19th Century, culminating in July 1853 when four United States war ships commanded by Commodore Matthew Calbraith Perry arrive in Edo Bay off present-day Tokyo. Under duress, the Japanese agree to open the country to trade with the US. Treaties with other Western powers follow.
At the same time, major changes begin to occur in Japanese society. The emperor reemerges as a preeminent figure. Feudalism and the old class system are abolished. Democratic practices are introduced. A constitution establishes limited representative government by a bicameral parliament (the Imperial Diet - Teikoku Gikai).
However, the cabinet is independent of the parliament and directly responsible to the emperor, who, because of his "divine" ancestry, holds ultimate power.
The country becomes more open to Western influences, ideas and innovations. The capital is relocated from Kyoto to Tokyo. Infrastructure and manufacturing facilities are modernised, along with the economic, legal and educational systems. Japan emerges as a major industrial power.
Japan's military institutions are also modernised. A small standing army is established, backed by a large reserve. Military service is made compulsory for all men. Foreign military advisers are engaged. Japanese cadets are sent to study at European and US military and navy schools.
A Supreme War Council is established. The council is headed by a chief-of-staff with direct access to the emperor and the ability to act independently of the government.
Towards the end of the 19th Century Japan becomes increasingly expansionist. Control of Taiwan is ceded to Japan after the First Sino-Japanese War (1894-95).
In 1904 Japan prevails in a war with Russian forces stationed in Manchuria (now Dongbei Pingyuan, north of Korea), giving Japan control of the Liaodong Peninsula and sealing its position as the preeminent power in the region.
Korea is made a Japanese protectorate in 1905, then fully colonised in 1910.
Following the final collapse of the Chinese Imperial Government at the start of the 20th Century, Japan sees a chance to further expand its empire.
The Japanese military is steeped in the tradition of unquestioning loyalty to the emperor. Commands from superior officers are regarded as equivalent to commands from the emperor himself. Military leaders have direct access to the emperor and the authority to transmit his pronouncements directly to the troops. The emperor is considered divine and the seat of ultimate power.