Let’s deal with the sex bit first. Nobuyoshi Araki, Japan’s most fanatically popular photographer, has made a name for himself in the West for tying up seminaked Japanese women in ropes, suspending them from the ceiling of his studio and then taking their portraits. Sometimes he photographs them in the gorgeous, loosely flapping folds of silk kimonos with a plastic lizard or perhaps an iguanodon creeping silently up their exposed thighs. The kinkiest — though this is debatable — is the series depicting a schoolgirl lying across a table, her knickers abandoned, a schoolboy and strawberry jam. Araki’s take on sex is rather more than a glimpse of stocking.

This probably seems bizarrely raunchy in a society which bans depictions of pubic hair and genitalia. (When Madonna’s book Sex first arrived in Japan, customs officials at Narita airport spent weeks searching for every last sprig of pubic hair and earnestly concealing the offending articles.) But if Araki’s photographs sound shocking, it is worth noting that Japan’s art of the past did not hold back with its explicit depictions of sex. Obvious precedents exist in the highly erotic shunga, the 18th and early 19th-century woodblock prints which reveal every conceivable sexual position in graphic detail. Araki’s work is no more scandalous than these still-treasured prints, and he is merely following in the hallowed footsteps of many other provocative 20th-century photographers in wishing to expose everything that society chooses to repress and conceal.

It’s not as if photography and sex is a new combination. You don’t have to look very hard to find a rich international history of pornographic photography, offered under the table ever since the invention of the medium, and an even richer contemporary body of work which now finds itself on gallery walls: Cindy Sherman’s prosthesis sex, Robert Mapplethorpe’s reverent portraits of erections, Nan Goldin’s lank-haired depressive sex and Larry Clark’s teenaged fondlers. Like Araki, these artists are showing off their familiarity with transgression.

But the one thing we should remember about Araki is that sex is only one (highly sensationalised) element of his work. He has been a hyperactive, unflaggingly prolific photographer for 50 years. He has photographed flowers, food, bicycles, cats, traditional Tokyo, people on the subway and, with great tenderness over many years, his wife, who died aged 42 in 1990. He has a catholic curiosity and a demonic energy for his work, which means he takes photographs day in day out, spewing forth a panoply of images without any apparent hierarchical distinction. More than 300 books have been published by or about Araki, and within this huge body of work the atmosphere of the age and the smell and the texture of his times are constantly and palpably evoked.

Araki was born in 1940 in the old shitamachi quarter of Tokyo, the son of a craftsman making geta clogs who was also an amateur photographer. A year later Japan entered the Second World War. He began taking photographs while still at primary school and then in 1959 enrolled in the department of photography and printing at Chiba University.

From there he entered Dentsu, one of Japan’s leading advertising agencies and, for creative (or rebellious) graduates, the holy grail of employment. Dentsu had all the facilities Araki needed to experiment with the camera, but its ethos was conservative, and he reacted instinctivelywith subversive work, undermining the predictable nature of photographic advertising. While at Dentsu he won the highly regarded Taiyo Prize for Satchin, a series of portraits of young boys playing in a shitamachi neighbourhood, their happiness and vitality undimmed by postwar poverty.

Japan was undergoing rapid and overwhelming changes shaped by its defeat in the war, by American occupation and by its rapid transformation into a modern urban society. There was the inescapable fact of two atom bombs. Expressways now sliced through the city and high-rise office blocks appeared. A new driving energy, sex, modernisation and liberal Western customs were infiltrating Japan and forming new hybrids with traditional culture. It is only in the context of these dramatic changes that we can understand Araki’s raw energy and productivity.

In 1971 he published Sentimental Journey, a record of his honeymoon, and a year later he left Dentsu to pursue his career as a freelance photographer. He began walking the streets of Tokyo, snapping away on impulse and intuition in response to the chance events and crazy rhythms of modern life. A pulsing, ambiguous stream of imagery spewed from his camera for years, and then in 1990 his beloved wife died.

In response Araki embarked on a vast range of new projects, conveying life in the raw. He also developed his style of erotic photographs. His work began to be shown in major exhibitions abroad and at the same time he became hugely popular in Japan.

One reason is that his photographs are redolent with the ambiguous Japanese quality of nostalgia. They deal with the sense of disconnection and malaise felt in a rapidly altering world where values have been shaken to their foundations. They give meaning to Japan’s changing times.

Araki: Self, Life, Death is at the Barbican Art Gallery, EC2 (0845 1216828), from Oct 6 to Jan 22