Falling Blossom by Peter Pagnamenta & Momoko Williams

The love letters on which this achingly sad true story is based were found in a Japanese trunk in 1982. There were 800 of them in all, rolled up and still in their original envelopes, studded with plump wax seals and foreign stamps. Some of the letters, written in archaic Japanese script, were six feet long. Desiccated pressed leaves, poppies and forget-me-nots fell from the envelopes.

Arthur Hart-Synnot, the author of the letters, was the son of a British land-owning Major-General. Masa Suzuki, the woman he fell in love with, was the daughter of a Japanese barber. A potent mixture of the class system, World Wars, serious injury and financial hardship ultimately kept the two of them apart, but not before they had had two sons together.

Peter Pagnamenta, the former editor of Panorama, and Momoko Williams have constructed an intricate edifice from the letters. Unlike the version of this story published in Japan in 1998, Falling Blossom builds a complete historical picture of Britain's relations with Japan from the turn of the 20th century to the end of the Second World War. It was Arthur and Masa's tragedy to play out their lives as minor actors in the chorus of world politics. They spent many more years apart than they ever spent together.

Masa was a deeply traditional Japanese woman. She would serve her father and brothers their meals and kneel in obedience while the men ate. Arthur, meawhile, was taught to be restrained and not to show emotion. Generations of his family had been decorated soldiers and he never questioned his own role as a military man. Masa had already been married by the time she met Arthur. Her family arranged a match when she was 20. She was a mother at 21 and divorced by her husband at 22. As the law dictated, her husband took the baby girl with him and handed her over to his new wife. Masa was a woman used to accepting her fate.

The skill of Pagnamenta and Williams lies in creating this fascinating story from Arthur's letters alone. None of Masa's to him survives. Arthur's letters reveal that their first son, Kiyoshi, was born in 1906. Typically, Arthur was jealous. "Kiyoshi is a lucky child. I am a little envious of him. I said so before he was born. I am a selfish man so I want to have my darling's heart all to myself, but because of him I have only half, haven't I?"

By 1910 Arthur was fixated on the idea that Masa should leave Japan and live with him in England. "You must come with me," he wrote to her in his formal Japanese script, "and I am sure you will agree because you love me." But the devoted Masa refused to give in this time. It was the year that their second son Hideo was born and Masa couldn't bear to leave her family and her home for a country where she expected to be ignored and despised. Arthur barely mentioned Hideo in his letters again. By the time the child died at the age of six, his father had only seen him three times.

Years went by, but Arthur continued to send money and promises that they would be together and Masa continued to write back. The touching and intense correspondence was unbroken. That is, until the day Masa received a letter from Arthur which changed everything between them for ever.

Falling Blossom is a meticulous and entrancing work, occasionally let down by a rather bizarre writing style. In an attempt to reinforce its journalistic credentials as well as its scholarship, the authors resort to chatty shorthand. "When the Foreign Secretary, Lord Lansdowne, said war now seemed inevitable, many Britons were enthusiastic at the prospect of their traditional enemy from the days of the Crimea being attacked, and the Russian bear biffed, always provided they were not drawn in themselves by the terms of the alliance."

Biffed bears aside, Falling Blossom is touching, revealing and erudite. Pagnamenta and Williams must be in part bereft and in part relieved that the whole painstaking task is finally over.