Postcard from Barcelona: All for a gaudy harlequin: Justin Webster on an unusual love affair between Japan and Barcelona

Why the Japanese have fallen so heavily for Barcelona is an enigma that has its residents puzzled. Catalonia is the region of Europe in which the Japanese have most concentrated their manufacturing investments: modern warehouses bearing the household names of Sony, Honda, Panasonic and Sanyo line the road going north out of its capital. The brand new, luxurious Hotel Arts which overlooks the city from one of the two Olympic skyscrapers on the coast is owned by Sogo, the equally luxurious Japanese retailer. All this might be explained by trends in unit labour costs and the European single market. But when a Japanese sculptor, Sotoo, joined in on the slowly-progressing century-old building of the Sagrada Familia, Gaudi's unfinished modernist cathedral in Barcelona, there appeared to be a more mysterious affinity at work.

Some Catalans talk of a subtle invasion; others are flattered by the attention, as if it confirms what they have all along suspected: that it takes an advanced, intelligent nation from the other side of the world to appreciate the qualities that the dimwits in Madrid have failed to notice for so long. Catalans are industrious - over money they are either mean or shrewd depending on your point of view - and they have their own language, with a literary tradition dating back to days of the national hero, Wilfred the Hairy, in the middle ages. A quick way to double the pulse of a Catalan is to ask if he or she is speaking a dialect of Spanish.

So it was definitely a shrewd move on the part of a publisher in Barcelona, Edicions La Campana, to bring out a book which deals with the Japanese enigma while at the same time supplying a frisson of pleasure for Catalans who have had to defend their language against confused foreigners. Catalonia and a Japanese is written by a Japanese, Ko Tazawa - but he wrote it in Catalan.

Although Ko Tazawa first came into contact with Catalonia and Spain as a trainee banker 25 years ago, his story shows how he quickly developed into an unconventional Japanese; it might even serve as a cautionary tale for any personnel managers of Japanese multinationals who are tempted to go native. By the time his company decided to send him back to Japan, Ko Tazawa had read Don Quixote, married a Japanese woman whom he had met at language school, and made Spanish friends. They taught him that Japanese work habits were not really suited for getting the maximum possible mileage out of life.

Consequently, he did not last long as a bank manager back in Kobe, where below fever-pitch enthusiasm for work is immediately detected. Instead, while earning his living as an interpreter, he went back to university, wrote a thesis on Catalonia, and eventually got what he really wanted, a teaching post as a philologist.

From his new perspective he compares the two cultures, but he is now himself bemused by the workings of Japanese companies, for example the custom of Saabisu Zangyo or unpaid extra hours. 'Workers do not declare the real number of hours worked,' he explains. 'They declare a lot fewer hours, and earn a lot less. Why? It's difficult to know exactly why.' Despite his self-effacing style there is no doubt that he thinks his compatriots are behaving like sheep.

The Japanese taste for Catalonia dates, he reveals, from a drinks advertisement in the second half of the 1980s which showed a harlequin dancing in the Parc Guell, the failed residential development designed by Gaudi, which is now one of Barcelona's best-known sights. From that moment Gaudi became to the Japanese what Madame Butterfly is in the West, reaching such a high point of popularity that a 'Love Hotel' in Japan was built in the form of the Sagrada Familia. Japanese package tours started to include Barcelona along with Paris, Rome and London. They were dazzled by its - no other word for it - gaudiness.

But the things that attracted Ko Tazawa to Catalan and set him on his mission to learn the language, are exactly the same as those that some foreigners complain about. For practical purposes, you can get by in Catalonia with Castilian Spanish. But someone who speaks only Castilian and arrives in Barcelona for the first time will be either intrigued or infuriated; there are plenty of signs or conversations or libraries that are closed to a non-Catalan speaker.

Ko Tazawa likens his own reaction to this predicament to falling in love. His book is an antidote to all those Catalans who have suffered real or imagined slights to their language and so it is not surprising that it spent four weeks on the daily La Vanguardia's bestseller list. As for the enigma, it provides another illustration for which there is no simple explanation.