Mr Oe - or, local style, Oe-san - had warned me in advance that I'd need to bring a translator along, because his English wasn't really up to snuff, but this proved to be unduly modest. Thanks, in part, to a recent stint of teaching at Princeton, Oe-san speaks a faltering but pretty serviceable version of our language, making up in passion and narrative drive what he lacks in precision. My interpreter, Tomoko, who was plainly rather awed at being in the presence of the great man, had nothing to do except sit up and pay attention.
One of Oe-san's stories went like this. He had come back tired and sad from a visit to Takemitsu's sick-bed, switched on the radio and listened to a broadcast of Bach's St Matthew Passion. It seemed a particularly moving performance, and he was harrowed by the lines in which Jesus speaks of his heart as a chalice for blood. He went to sleep with an ache in his own heart, and when he woke the next morning the journalists were on the phone to tell him that Takemitsu-san was dead. It was only a few days later that Takemitsu's widow said to him that the composer had been listening to the very same broadcast.
While Oe-san was telling us this and other equally affecting stories, I became aware that Tomoko was quietly snuffling. Because the guidebooks tell you that Japanese people tend to consider it a gross indelicacy to blow your nose in public, I at first assumed that she was trying stoically to contain a sneeze. Only later did she confide in me that she was in fact trying to fight back the tears. She had my sympathy: Oe-san's grief was palpable, and it was nearly the end of a long and hectic day crammed with such fond and mournful recollections, as well as plenty of lighter moments.
I'd arrived in Tokyo the night before, with the brief of fleshing out the standard British vision of Toru Takemitsu by speaking to some of the people who had known him best - in other words, to some of the most celebrated and influential people in Japanese cultural life, since Takemitsu's peer group was like a Who's Who of the nation's arts.
I'd begun this crowded day by meeting Japan's leading poet, Shuntaro Tanikawa. Though Tanikawa-san has only just been published here, he has already produced some 60 volumes of poetry, many of them best-sellers (read it and blubber, British bards), has been translated into 15 languages and is the translator of the Peanuts comic strip.
Tanikawa-san was at pains to stress that, as far as he can tell, we in the West have quite the wrong idea about Takemitsu. Though he was utterly committed to his art, Takemitsu the man was anything but the solemn, ethereal creature who stares dreamily into the cosmos, fingers steepled, on CD covers.
"Some critics and some audiences, think him very... how can I put it... like an alien." (This is quite true; in fact, one of the cuttings I'd been reading on the flight over compared Takemitsu to ET the extra-terrestrial) "...or like an oriental philosopher, and they think that he must be very hard to talk to. But he's not that kind of person. He likes joking, he likes cheap movies and cheap novels. When we were young, Takemitsu and myself are fond of Westerns, and we liked the bad guys who are good at pistols, so we are using toy popguns" - Tanikawa-san starts to guffaw at the memory - "and are imitating Western heroes."
When I remarked that Takemitsu seems to have had no problems reconciling a hearty appetite for pop culture with his exalted vocation, Tanikawa agreed fervently: "Most composers of modern music and most poets kind of divide high culture and low culture, but we don't have those kinds of prejudice; we like what we like. We try to enjoy life."
Apart from his talent, it was this zestfully unsnobbish attitude that made Takemitsu such a successful composer for films - he wrote the scores for more than 90 movies by such directors as Teshigahara, Kobayashi and, most famously, Akira Kurosawa, for whom he provided the memorable soundtrack music of Ran (1985) in the style of Mahler.
Before we parted, Tanikawa-san read me an English version of a poem he wrote for Takemitsu in the Sixties, which contained the lines:
out of the void of his healed
lungs and heart,
air is exhaled
to mingle with the air of spring.
"Healed lungs" was lost on me, but I had my explanation less than an hour later, when I travelled over to a hotel in the swanky Ginza district at Tokyo to meet Takemitsu's widow, Asaka, and his daughter Maki.
"In his later years," Asaka Takemitsu recalled, her husband "was a very bright and sociable person, but when I first met him he was very sickly. He had holes in his lungs, and his father had died early, so his mother had to go out to work, but in spite of their financial difficulties he really wanted to study music. When I met him, he almost forced me into taking care of him; he needed to be taken care of."
Both mother and daughter proved to be striking presences - Asaka Takemitsu dressed in a smart version of Bohemian, with a loose, dark-blue linen shirt and sporting a huge shock of ebony hair; Maki, who has lived in Boston, was in western-style T-shirt and sunglasses. She recalls her father with good-humoured affection: "He was more like a big brother to me; he treated me as a friend, and he never really told me to do this or not to do that, which normal fathers do."
Did he encourage you to be creative? "No, no, never... in fact one thing he did tell me was never to be a musician, or marry a musician, because it's so hard to make a living. The only other thing he told me was to go to movies - watch movies, watch movies, watch movies!"
And what, I asked Maki, was her strongest memory of her father?
Her reply echoed Tanikawa's: "Well, he certainly wasn't like that," she said, pointing to a conventionally "spiritual" portrait of the composer on a concert programme. "He loved to play The Beatles or jazz on the piano; he loved to dance around and play, he loved socialising and drinking with other people, especially writers and painters and younger musicians... he was really a lot of fun."
There was much more to talk about, but we had a strict timetable to keep, including interviews with one of Japan's leading industrialists, Seiji Tsutsumi (he moonlights as a poet under the pseudonym "Takashi Tsujii"); with members of the musical ensemble Reigakusha, who are coming to Britain later this month to play both their traditional Gakaku compositions and Takemitsu's Gakaku composition In an Autumn Garden (1973); and, finally, with Kenzaburo Oe.
The first thing Oe-san stresses about his late friend is that without Takemitsu, he would never have become a writer. Although Takemitsu was often self-conscious about his lack of formal education, Oe is happy to admit that the composer was his "tutor" in almost every field, "not just music, but architecture, painting, sociology... yes, and literature". In Oe's view, Takemitsu's true genius was not simply his talent as a composer but his generosity, his ability to act as a catalyst for the talents of others, and his social skills. Takemitsu, Oe-san insisted, was the man who single-handedly created Japan's modern cultural elite - its first clerisy of self-conscious, politically aware intellectuals.
As we prepared to leave, Oe-san invited us to wait a moment while he played us a track from his son Hikari's latest CD. "There is only one genius in our family," said the proud father; as readers of Oe's painfully autobiographical novel A Personal Matter may recall, Hikari was born with a serious malformation of the brain, and some doctors thought the baby should be left to die. Oe decided otherwise. Years later, his son began to display a near-miraculous gift for music; and, just as he did for other artists, Takemitsu encouraged the young man's career. Hikari's latest piece is an elegy to Takemitsu - a work in three short movements, of which the second, Fight, represents an evening when Takemitsu and the novelist argued fiercely over an opera they were playing, but which was never completed.
Oe swayed gently in rhythm with his son's piano music. "Very fine," I said when it came to an end. "From everything I've heard today, Takemitsu- san sounds like a wonderful person." Oe-san nods. "Yes. He was a wonderful person."
`Spirit Garden', a retrospective of Takemitsu's music, runs from tomorrow until 28 October at the Royal Festival Hall in London. Telephone 0171- 960 4242