He died with cruel, mystifying suddenness in a nondescript Amsterdam hotel early in 1983, but that coaxing, mellifluous voice can still be affectionately heard, when we listen hard enough, on a hundred Welsh touchlines.

Carwyn, just Carwyn: the name continues to bring a glow of treasured reminiscence, followed by those eloquent, perplexed sighs. There was never a greater influence on the way rugby should be played in Wales. Yet, for complex, contrary, needless, self-induced reasons, he was not appointed the national coach. He was the man everyone knew - and no one knew.

Along every valley, in every pit village, every tucked-away rugby ground of steaming winter breaths, they doted on his wisdom and the melodic words - about sport or life - which he gave so freely to anyone who asked. They basked in his coaching triumphs for Llanelli and the Lions. They travelled miles, many of them miners' sons like himself, to hear him speak. They revered him as a chapel deacon and a white-robed druid.

Many contended he was a rugby guru without equal. They were conscious of the lyrical quality that he insisted on bringing to the game, whether first as an instinctive outside-half and then as a gentle, single-minded coach, the mentor to so many. What few of them knew was the measure of the pain he suffered in his privacy.

Perhaps it is the voice that we remember best of all. It was musical and sweetly tuned, too calm, one would have thought, for the biting winds of an exposed touchline. That voice, fashioned by the hymnal, was rarely raised in rebuke at the expense of a player; it increased fractionally in decibels only when someone, in his cups, took a sly, insensitive dig at Carwyn's undeviating political zeal and "Welshness".

The voice could be mesmeric as his unbridled conversation weaved joyfully in and out of literature, the arts and the brotherhood of man. He loved talking, philosophising, paying homage to genius, whether he saw it at the time as Beethoven or Phil Bennett. He had a reasoned opinion about most things. Backed by scholarship and a sharp brain, softened by the chuckle that was seldom far away, he was not easily shifted.

On one of my visits to Cardiff, long after the close of play, the two of us were drinking together in the small bar above the dressing rooms. I told Carwyn it was time to motor back to my home in Bristol. "Not yet ... Let's have another drink together. We have much to talk about. Tell me about Bristol Rovers. Or Mike Procter. Or John Blake's Bristol - did he really have that lovely rugby team of his running all the time?"

There was almost a kind of desperation in those cascading questions, as he blurted out the disparate potential starting points of conversation. Before I had offered any kind of reply he was at the bar, buying us another double gin. I was flattered, of course I was, that he wished to stay chatting with me. At the same time, I came to one irreversible conclusion. He was a painfully lonely man.

Cliff Morgan was among James' friends. They traded reminiscences by the dozen; they sang hymns together. On that great New Zealand tour, when Carwyn was the coach and Cliff was heavily involved in broadcasting, there was a knock on Morgan's door at half past eleven one evening. "And there he was, Carwyn, clutching a bottle of gin with the tonic stuck in his breast pocket. Just to see him there made one feel better. He stayed for hours. We talked about everything - the scoring of tries, the rights of man."

Carwyn stayed with Cliff and his wife immediately before going to Holland on that last fateful break. He was due back to accompany Cliff for a match at Twickenham.

"Rugby is a gregarious game and I think, on reflection, it gave him some relief from his loneliness." Morgan pauses, then recalls: "Once in a moment of some confidence, he suddenly said to me, "There is a great loneliness upon me, you know." I was struck by his use of words.

It's probably true to say that Carwyn saw rugby, for all its physical whims, as a cerebral game. The brawling and blaspheming didn't interest him. He encouraged his teams to play with their heads, to think what they had to do, to reject stereotyped notions and the temptations to opt for caution (and boredom). "Take a risk or two, make a few mistakes. As long as you are adventurers, I won't mind."

So why, for heaven's sake, why? Why did he not coach the Welsh team? It had surely, in every logical sense, to be him in succession to Clive Rowlands.

In many ways, he was very much part of Wales' inner establishment: Welsh-speaking, white-robed, steeped in the cultures of his native heath, erudite. Yet when it came to rugby, at the highest level in his own country, he was critical and despaired of entrenched attitudes. Maybe his popularity and strongly held views worked against him. Some of the game's hierarchy were exceedingly wary of him. He was too much of an individualist, not receptive to a second point of view, they said. All right, he wanted to run the whole show - and he knew he could do it better than they could.

He could be too tenacious and unyielding in an argument. His critics called him aloof and distant. Some of his silences were misunderstood. "You'd sooner talk rugby with a couple of dozen schoolkids than with some of the WRU elders."

Carwyn died, aged 53, from a heart attack in his hotel bedroom. He died alone while having a shave and he banged his head on the bath as he fell. A doctor recorded natural causes. There was no postmortem - only profound shock back in Wales and some inevitable conjecture. Was there a cover-up? Did those recurrent rumours about his sexuality have any substance? Several newspapers received a colourful account from the continent of Carwyn's last hours. To their eternal credit, they spiked the story.

Clem Thomas, his captain from schoolboy days, who graphically described him as "a bard among bricklayers", was aware of how well Carwyn's older sister, Gwen, mothered him. "But he had no wife or children to confide in. He was in many ways a man in torment. He was private and lonely and found refuge in his own and his beloved country's passion for the game of rugby."

We can't escape the politics in any study of James. His nationalist zeal was evident from college days. He ended up the president of Plaid Cymru at Aberystwyth; in the years that followed his political oratory was unfailing and at times counterproductive. He turned up at demonstrations. He opposed the official investiture of Prince Charles at Caernarfon and there is some evidence that Special Branch were keeping an eye on his activities. He retained a solid integrity. That was why he rejected an OBE after the eulogies extended to him over the Lions tour.

In 1970 he stood at Llanelli as the Plaid Cymru candidate in the general election. Labour had a big majority and he always knew his chances were slim. Against most of the predictions he polled nearly 17%, and didn't lose his deposit.

He died a sick man. He'd put on weight, was still smoking 50 a day and had a consistent thirst, with or without company. He now watched matches, as a broadcaster or journalist, and missed the sweat of the dressing room. Why, for a man so friendly by nature, did he lack friends when he needed them most?

Carwyn James remains a riddle.

 This extract on Carwyn James, once a respected rugby writer for the Guardian, is taken from a set of 12 sporting character studies by David Foot. Readers can order a copy of Foot's new book Fragments of Idolatry (Fairfield Books) for £15, including free first class p&p. Freephone 0800 3166 102 or send your order with a UK cheque, payable to The Guardian to, Freepost Books, LON3590, London, W3 6BR.