On a backstreet in the Nihonbashi district of Tokyo, between a seafood wholesaler and a jewellery shop, stands a simple monument. It marks the former site, the inscription reads, of the home of William Adams, the first English person to reach Japan, and the inspiration for one of the standout TV series of this year.

Though it says Adams rendered “valuable services in foreign affairs”, the memorial is a strangely inconspicuous tribute to a man who, more than 400 years after his death, remains an unbreakable thread running through Anglo-Japanese relations, and whose on-screen portrayal continues to trigger debate.

The release this month of the Disney+ series Shōgun has reignited interest in the navigator from Kent whose talents were endless: shipbuilding, gunnery, mathematics, geography, trade negotiation and diplomacy, and, most notable of all, personal skills that saw him become friend and trusted adviser to the feudal warlord Tokugawa Ieyasu.

Born in Gillingham in 1564, Adams was the sole Englishman aboard Dutch merchant ship De Liefde when it drifted into Usuki Bay in south-west Japan in April 1600. Adams and 23 Dutchmen were the only survivors of a fleet of five ships and 500 men that had set out from Rotterdam almost two years earlier. Of the 23, only nine, Adams among them, were strong enough to disembark.

Locally based Jesuit missionaries tried to have Adams executed for piracy, but he avoided that fate and went on to become Japan’s first foreign samurai, forging a link between that distant, mysterious archipelago and the homeland he would never see again. His story has inspired a bestselling novel – James Clavell’s classic 1975 work Shōgun, with Adams’s name changed to John Blackthorne – and a 1980 miniseries starring Richard Chamberlain.

Those earlier retellings of Adams’s extraordinary rise through the hierarchy of a warring Japan largely isolated from the rest of the world have fascinated generations of readers and viewers. But their creators have also been accused – unfairly for some – of perpetuating the stereotypes that informed other tales of foreign encounters with Japan, including The Last Samurai and Lost In Translation.

The launch of the 10-part series has triggered a conversation about what, in an age of cultural strife, the story of the “blue-eyed samurai” can teach us about assimilation and respect.

Starring Japanese actor Hiroyuki Sanada as warlord Yoshii Toranaga, Cosmo Jarvis as John Blackthorne and Anna Sawai as Lady Toda Mariko, the drama has won positive reviews for its Japanese cast, meticulous production and its creators’ attempt to accurately portray the unspeakable violence and cultural refinement of 17th-century Japan.

“They have taken great care over that,” said film and TV critic Yuki Saruwatari. “Some have compared it to Game of Thrones, and I think they’re right. It contains shocking violence, death, betrayal, manipulation…”

But its depiction of the navigator has divided members of the William Adams Club, formed in Tokyo in 2015 by fans of Adams and his role in Anglo-Japanese relations.

Member and Japan resident Chris Wells said the first episode had left him fuming. “It is damaging to the memory of William Adams,” he said, adding that he was not the only member of the club to feel let down.

In his account of his arrival in Usuki, in modern-day Oita prefecture, Adams tells of the kindness he and other crew members were shown by local people, but in the TV series, their arrival is the catalyst for a violent confrontation.

“I find the first episode really insulting to the Japanese,” Wells said. “The people of Usuki took those sailors off that boat and nursed them back to health. It’s a typical Hollywood representation of the Japanese people.”

Adams would eventually be known in his adopted home as Miura Anjin – combining the name of the peninsula near Tokyo where he was awarded an estate and the Japanese word for pilot. In 2020, on the 400th anniversary of his death, the William Adams Club unveiled a sculpture of their hero in the grounds of the British embassy, three years after his remains were discovered in Hirado, Nagasaki prefecture.

Japanese schoolchildren learn about Miura Anjin’s exploits and his role in connecting two island nations at opposite ends of the world.

“His must be one of the great examples of assimilation into the highest reaches of a foreign culture,” said Hiromi Rogers, author of Anjin: The Life and Times of Samurai William Adams. “There is the scale of his ascent in Japanese society … from wretched prisoner condemned to crucifixion, to adviser to the Shōgun and high-ranking hatamoto samurai with an estate and 90 servants.

“Nothing like that has happened since, certainly in Japan, which is not the easiest of cultures into which to assimilate.”

So can modern-day migrants to Japan – particularly those from an increasingly insular, post-Brexit Britain – learn anything from Adams?

“I think he recognised that Japanese and British culture had much in common,” said Giles Milton, author of Samurai William: The Adventurer Who Unlocked Japan.

“Both countries are islands. Both are inherently conservative, have an ingrained hierarchical structure and an interest in international trade. Adams showed great interest in and respect for Japanese society. This endeared him to the local population and enabled him to survive, and thrive, in Japan,” Milton said.

While they debate the merits of the Disney+ drama, members of the William Adams Club are united in their mission to set up a more prominent tribute to Adams on the site of his Nihonbashi home in recognition of his role in shaping a Japan that viewed the world with a combination of suspicion and intrigue.

“Adams was far from home with no way of getting back,” said Prof Thomas Lockley of Nihon University College of Law in Tokyo and author of forthcoming book A Gentleman from Japan, about the first Japanese visitor to England, in 1588.

“You can either put yourself in a bad position and die, or meld into the world around you and make yourself useful … and that’s what Adams did.”

Adams, perhaps through necessity at first, went completely native, marrying the daughter of a Japanese official and going on to have two children, although he made arrangements to divide his considerable wealth between his families in Japan and England.

“He naturalised as a Japanese citizen,” Lockley said, “and I would say that he was part of the reason I decided to do the same. In that sense, I see him as my spiritual ancestor.”