He was called Lord Toranaga in James Clavell's book for the sake of artistic licence; it permitted a love interest for which there was no documentary proof. But the real Shogun who inspired the bestseller and subsequent television drama was Lord Tokugawa Ieyasu, one of the most outstanding figures in Japanese history and a lord still revered in his homeland 400 years after his death.
Now 30 years after Clavell's book was acclaimed for "[taking] the Western world into a completely different world", an exhibition at the Royal Armouries museum in Leeds is to tell the real-life story of the 17th-century leader.
Using more than 50 precious objects, most lent for the first time by the Nikko Toshogu shrine where the lord was buried after his death in 1616, the exhibition will explore his power and intelligence and show how he established a dynasty that ruled a newly stabilised and peaceful Japan for 250 years.
So sacred are some of the objects considered that two Shinto priests will safeguard their journey to Britain for the show, which will run from 6 June to 30 August. Shogun armour sent by Lord Tokugawa for King James I and still in the Royal Armouries collection will be a highlight. The diary of the British captain, John Saris, who brought the gifts to the king, will be lent by the British Library. But four-fifths of the exhibits will come from Japan, including decorative and functional items illustrating his martial prowess and his interests in astronomy and the art.
Yet when Lord Tokugawa was born in 1543, his domination could not have been predicted. He was the son of a minor territorial lord at a time when Japan had been riven with civil war for a couple of centuries. In the following decades, the feuding territorial lords were gradually overcome and united, under the warriors Oda Nobunaga and then Toyotomi Hideyoshi. Tokugawa Ieyasu, who fought his first battle aged 16 and would fight his last more than half a century later, had a tough training under both men. At one stage, he was forced to kill his wife while his first son committed suicide to satisfy lords who suspected him of disloyalty.
Upon Hideyoshi's death, Tokugawa swore allegiance to the warrior's family, but did prove disloyal when, in 1600, he fought and defeated Hideyoshi's supporters at the battle of Seki-ga-Hari, a bloody battle which saw 36,000 left dead or seriously injured in a single day.
After that, he was granted the title of Shogun, or military leader of Japan, which meant that he was running the country. While the ostensible rulers were Japan's emperors, from the 13th century they effectively abrogated power to the military. "The emperors were there in the imperial palace in Kyoto, powerless paupers, carrying out a few ceremonial duties," said Ian Bottomley, the senior curator of oriental arms and armour at the Royal Armouries.
What was extraordinary about Lord Tokugawa was that he did not simply consolidate his position in Japan. He began to look outwards to countries, such as Portugal and Holland, whose traders and missionaries had begun to make contact during the 16th century.
"What is quite staggering, really, is that he tried to establish diplomatic relations with the crowned heads of Europe," Mr Bottomley said. "Here was this country on the far side of the world which the people of Europe had hardly heard about. It was almost mythical. But Ieyasu sent diplomatic gifts to the kings of England, France and Spain and to the Pope. He also dealt with nearer countries like Thailand. He was putting Japan on the diplomatic map."
One of his main ways of doing so was through Will Adams, the Englishman who inspired Clavell's character, John Blackthorne, played by the actor Richard Chamberlain on television.
Adams, who was born in Kent in 1564, learned shipbuilding, astronomy and navigation as a shipyard apprentice before becoming a sailor. In 1598, he set sail with a Dutch fleet which became stranded in Japan after a typhoon and the crew imprisoned in a castle in Osaka on the Shogun's orders. But the Shogun took a liking to Adams and eventually made him a diplomatic and trade adviser, bestowing great privileges upon him as some recompense for refusing him permission to leave his court.
Mr Bottomley said Lord Tokugawa was a clever man who appreciated what he could learn from the young Englishman and saw the advantages that could be obtained by contact with the West. "A lot of people in Japan were very inward-looking," Mr Bottomley said. "But Ieyasu was a very learned man. He studied navigation and astronomy with Will Adams and was interested in the world. Adams was considered too valuable to be able to leave."
Tokugawa Ieyasu was Shogun for a couple of years before ceding power to one of his five sons. But effectively his rule continued until his death, bolstered by having his children in positions of authority across Japan and by tactics such as holding the wives and families of the territorial lords hostage at the Shogun palace at Edo (later Tokyo). He is remembered for his successful unification of Japan and for bequeathing it a long-absent stability through the establishment of the Tokugawa dynasty.
Mavis Pilbeam, the author of a children's book on Japan under the Shoguns and a British Museum librarian, said the relative peace enabled Japan's cultural life to flourish - painting, calligraphy, theatre and music were already a well-established part of upper-class life. "It was an extremely sophisticated court at Edo. The Shogun had their own artists. They had Noh-style theatre and music. They were very cultured in that way," she said. And all the textiles and cloths were fantastic. Silk was made in Japan at that time and there were high-class ceramics. They had mastered the art of porcelain, which they took from the Chinese and the Koreans. What happened under the Tokugawa Shogunate was that because of the comparative peace, it was a wonderful period for the arts, [such as] the Ukiyo-e school of floating world pictures."
Merchants, though at the bottom of the four-tier social order topped by the samurai, had money to spare on such delights because the warring had stopped. There was a proliferation of woodcut prints and more lavish textiles and ceramics. The British Museum is staging its own exhibition at the end of June of prints of heroes of the kabuki theatre in Osaka between 1789 and 1830.
Arms and armour became more ornamental as they were no longer required for real fighting, but became largely ceremonial.
The teachings of the Chinese philosopher Confucius, who advocated keeping people in their place amongst other things, gained prominence.
Yet, after Lord Tokugawa Ieyasu's death, many of these developments took place behind closed doors. From 1639 until the middle of the 19th century, Japan ceased dealing with all foreigners, bar the Dutch who were allowed trading rights at Nagasaki. The Shogun feared Westerners wanted to take the country over. Only in the middle of the 19th century did the Americans infiltrate Japanese isolation and the country re-opened to the West.
This prompted a renewed fascination with Japan as seen in the Gilbert and Sullivan operetta The Mikado and later in Puccini's opera Madame Butterfly as well as Japanese influence on garden design, the arts and crafts movement and even art nouveau, Ian Bottomley said. Japan was added to the Grand Tour after Europe, India and America. After a lull during the war, it was revived in the Sixties, ripe for Clavell's book in 1975, whichsold seven million copies. "What Clavell was writing was fiction. He changed names so he could play with history, but he didn't modify it much. He just didn't use the names Ieyasu or Will Adams," he said.
For the Royal Armouries, interest in Lord Tokugawa Ieyasu stemmed from his gift of the armour, which is now one of the most highly prized items in its collection. Peter Armstrong, the Armouries' director, said it had begun to forge a relationship with the Nikko shrine several years ago with a view to further understanding of the armour and other objects in its collections.
The shrine, now a World Heritage site, is one of the most visited in Japan though it was not Lord Tokugawa's original resting place. He was moved there by imperial decree a year after his death. This shrine, too, was deemed too modest and was extended using 4.5 million craftsmen and labourers working for 17 months at a cost of £200m in today's money. The receipts and wages bill are still kept within the shrine complex.
"It has taken about six or seven years to get them to release objects that are sacred," Mr Armstrong said. "It's like lending bibles from cathedrals."
Whether British visitors will grasp the sacred significance remains to be seen despite the Royal Armouries' best efforts to be sensitive. At the very least, this exhibition will show fans of Star Wars the cultural roots of the look of Darth Vader, an influence no one could have predicted in Edo 400 years ago.
The Life of Lord Tokugawa Ieyasu runs at Royal Armouries, Leeds, from 6 June to 30 August
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies