Ryuzo Sejima lived a full and varied life, being involved in Japan’s military growth and defeat, its postwar industrial development and its political and artistic activities. In his lifetime Japan developed from being a fledgeling industrial state, controlled by a ruling clique, to become an economic superpower.

Sejima was born in 1911, in Oyabe, Toyama prefecture, Japan, into a humble farming family. He turned his back on agriculture to enter the Army War College from which he graduated as the top student. This highly regarded military education set him on a course of steady progression in the army, serving as a staff officer in the Imperial Army headquarters where he developed his skills as a strategist.

During the war Sejima saw action on several fronts; the plans for the withdrawal from Guadalcanal in the Solomon Islands were primarily his, but it was for his involvement with the situation in Manchuria and the Soviet Union, both during the war and afterwards, that he was most noted.

The first half of the 20th century was a period of constant friction between Japan and Russia, beginning with Japan’s novice army gaining a victory in the Russo-Japanese War of 1904-05. This highlighted Japan’s rapidly increasing power on the world stage and was inspirational to the military culture in which Sejima grew up.

In July 1945 he was posted to the Kwantung army headquarters in Manchuria, China, where he was given the responsibility of negotiating a ceasefire settlement with the Soviet Union. Having failed to pacify the Soviet forces, Sejima was captured and then detained in a Siberian PoW camp for 11 years; for most of the period his family were not told whether he was dead or alive. His memoirs, Ikusanga-Sejima Ryuzo Kaisoroku, suggest that he believed Japan had made insufficient forecasts of the international situation and the power of the Allies.

Sejima was eventually freed by the Russians and returned to his country in 1956, determined to help to rebuild postwar Japan. He joined the Itochu Corporation, Osaka, and was credited with transforming what had been a modest textile-trading company into a dynamic, international firm, having adopted a restructuring programme that was strongly influenced by his military background.

His success at Itochu soon earned him a place on the company’s board. He also led the company to diversify into oil industry-related business and pioneered an alliance between the General Motors in the US and Isuzu Motors in 1971. He became chairman in 1978.

In 1981 Sejima was invited to join the second ad hoc Government Council of the Prime Minister, Yasuhiro Nakasone. This organisation, primarily concerned with administrative reform, paved the way for internal governmental changes, which resulted in some important privatisations and a cutback in the Civil Service. Influenced by the policies of Margaret Thatcher, Sejima was closely involved with the efforts to privatise the Nippon Telegraph, the Telephone Public Corporation and Japanese National Railways.

His influence was not restricted to domestic policy. As special envoy for Nakasone, he used his diplomatic skills and personal connections with the South Korean presidents, Park Chung Hee and Chun Doo Hwan, to help to organise a surprise visit for Nakasone in 1983. This was momentous as South Korea was Nakasone’s first overseas visit as prime minister. Sejima also had close relationships with subsequent Japanese Prime Ministers; Keizo Obuchi, Kiichi Miyazawa and Ryutaro Hashimoto.

As chairman of the Japan Art Association, Sejima spent the last 16 years of his life involved in the international arts world. In 1988, to commemorate the centenary of the association, a series of awards, the Praemium Imperiale, was established. The awards, which Sir Edward Heath, an international adviser to the Praemium Imperiale, often compared to the Nobel prizes for the arts, honoured artists who had made contributions in the fields of painting, sculpture, architecture, music and theatre/film. Other international advisers include Helmut Schmidt, Jacques Chirac, David Rockefeller Sr and Richard von Weizsäcker. Sejima represented the Japan Art Association as chairman at many Praemium Imperiale events in Japan and overseas, including correspondence with the Emperor and Empress of Japan and Prince and Princess Hitachi, as well as meetings with the Queen in both 1995 and 2000.

Although, as a former military strategist, Sejima’s involvement in politics has often been deemed controversial, Japan’s outgoing Prime Minister, Shinzo Abe, praised Sejima for “surviving before, during and after the war, particularly the 11 years of hardship in Siberia”.

Having lived through what was one of the most challenging periods in Japan’s history, Sejima’s life has been regarded by many as a personification of the recent evolution of his homeland.

Ryuzo Sejima, chairman of Itochu, was born on December 9, 1911. He died on September 4, 2007, aged 95