Like many children with autism, 13- year-old Naoki Higashida had spent years locked inside his own seemingly impenetrable world. Without the power of speech his feelings were expressed through explosions of temper, panic attacks and tears.
For those who loved and supported him - as for so many others in their position – Naoki's inner feelings remained a painful and frustrating mystery.
Then, one day, a teacher gave Naoki a simple cardboard keyboard. He began to share his world, pointing at the letters to spell out his feelings - letter by letter, word by word. Now, eight years after they were first written, Naoki's thoughts are giving a remarkable insight not only into his own emotions, wishes and quirky humour, but also into those of countless other children on the autistic spectrum.
Acclaimed novelist David Mitchell (Cloud Atlas, the Thousand Autumns of Jacob de Zoet) and his wife Keiko Yoshida have translated Naoki's book, The Reason I Jump, into English, creating an unexpected best-seller and, they hope, a little bit more understanding about autism.
Mitchell's motives for this latest project are deeply personal. Five years ago his son was diagnosed with autism.
The couple were immediately bombarded with sympathy and advice – most of it well- intentioned, not much of it particularly relevant to their situation. There is already, a huge publishing industry fuelled by autism. Yet amongst the academic texts, memoirs written by other parents, and autobiographies produced by adults on the autistic spectrum, Mitchell found little which gave him a particular insight into his son's world.
In the introduction Mitchell wrote to accompany Naoki's words, he describes how finding The Reason I Jump changed that. His wife had heard about the book on the internet and ordered a copy from her native Japan. Finally the couple found writing which offered a real connection with their son. The book was, he writes "a revelatory godsend. If felt as if, for the first time, our own son was talking to us about what was happening inside his head, through Naoki's words."
Most exhilarating for Mitchell and Keiko was the proof that despite the communication and behavioural difficulties of autism, a mind affected by the condition could be just as inquisitive, subtle and complex as anyone else's. Naoki may have struggled to express his emotions vocally, but he was as capable of feeling them as any other 13-year-old.
The book is split into a series of questions to which Naoki aims to provide answers – his own quasi FAQ list. The topics range widely, from his views on running races (running is fun, racing is not) and being in the water (it is quiet and he is able to feel "at one with the pulse of time" – a concept from which he later explains he usually feels "semi-detached), to the huge questions such as his thoughts on autism itself, why he struggles to hold a conversation and whether he would like to be normal.
Naoki cannot find answers to all the questions he poses, but his responses are unswervingly honest, thoughtful and often very moving. His need to make himself understood, and the pain he feels when he is unable to do this, is clear.
"We really badly want you to understand what's going on inside our hearts and minds," he writes. "And basically, my feelings are pretty much the same as yours."
Trying to operate his body is, he explains, like "remote- controlling a faulty robot".
Naoki challenges several of the widely held myths about autism – most strikingly the notions that children with the condition prefer to be alone and that they are unable to feel empathy.
"I can't believe that anyone born as a human being really wants to be left all on their own," he points out. "The truth is, we'd love to be with other people. But because things never, ever go right, we end up getting used to being alone, without even noticing this is happening."
He frequently voices anguish at the pain he knows his condition causes those who love him. This is a child who very clearly thinks about the feelings of others, even if he is not always able to demonstrate this outwardly.
"The hardest ordeal for us is the idea that we are causing grief for other people. We can put up with our own hardships okay, but the thought that our lives are the source of other people's unhappiness, that's plain unbearable."
While moments of the book make heart-rending reading, there are also plenty which are hopeful and inspirational. He describes his love of going out for walks and his relationship with nature as one in simple contrast to his fraught social interactions.
"Just by looking at nature, I feel as if I'm being swallowed up into it, and in that moment I get the sensation that my body's now a speck, a speck from long before I was born, a speck that is melting into nature herself. This sensation is so amazing that I forget that I'm a human being and one with special needs to boot."
Uplifting too – for Naoki in a literal sense – is his explanation of his need to jump (frequent repetitive actions like jumping, spinning, flapping and flicking fingers are a very common trait in autism).
People assume, Naoki asserts, that he is feeling very little as he bounces up and down. In fact, he explains, "it's as if my feelings are going up to the sky....When I'm jumping I can feel my body parts really well too – my bounding legs and my clapping hands – and that makes me feel so, so good." It is, he goes on to say, a way of freeing his body from the ropes he often feels entrap it.
Naoki writes little stories for himself, to try and make sense of his feelings, and several of these are included in the book. The final one, I'm Right Here, is a beautifully written tale about a boy who dies in an accident and his efforts to comfort his grieving parents from beyond the grave. It is, Naoki, explains, an illustration of the pain of struggling to express his feelings to those he loves.
Like the rest of the book it is a truly touching glimpse into the world of an emotionally literate, thoughtful and very clever young boy - and a sobering reminder to challenge our preconceptions about those who are different.
The Reason I Jump: One Boy's Voice from the Silence of Autism By Naoki Higashida, (Sceptre, £12.99)