SAMURAI AND SILK; A Japanese and American Heritage. By Haru Matsukata Reischauer. Harvard University Press. 371 pp. $20.

PEOPLE whose childhoods have been divided between different cultures can end up writing as a way to reconcile the different, often contradictory demands their backgrounds make on the adult self. Their work may take on a poignancy beyond keenness of observation because the subject is not just academic to the writer. From a dual vantage point, such people often employ a privileged sensitivity to both elements of their heritage.

Privileged sensitivity is what we ought to expect from Haru Matsukata Reischauer in Samurai and Silk, a dual biography of her maternal and paternal grandfathers. Yet despite the fascinating material she addresses and her own intimate relationship to it, te book is a flat account of what should be utterly engrossing.

Haru's mother, Miyo Arai, was born in New York and brought up in Old Greenwich, Connecticut. One of America's first nisei (second-generation Japanese Americans), Miyo Arai was more American than Japanese in many of her ideas. Despite these maidenly handicaps, she was married to a younger son of statesman Masayoshi Matsukata, and Miyo dutifully joined her husband's family in Japan. Her second daughter, Haru, a Japanese citizen with what was an unusual bi-cultural background at that time, ended up marrying Harvard professor and later U.S. Ambassador to Japan Edwin Reischauer. Given the marvelous opportunities afforded by kith and kin, Haru Reischauer was positioned to write something special. Our disappointment is all the more keen.

Her primary subjects could hardly hold more intrinsic interest: grandfather Matsukata (subject of Part I) was a rural samurai instrumental in shaping the new imperial Meiji state and twice prime minister; grandfather Arai (Part II) was one of the first Japanese international businessmen, making his home in America while building Japan's export reserves in the silk trade. The lives of these two men and their numerous and prominent progeny (Part III, Descendants and Relatives) span one of the most tumultuous, interesting periods of modern world history: from Japan's mid-19th-century renunciation of feudalism and bootstrapped leap into the modern world to the country's economic preeminence in the 1980s.

The biography of Masayoshi Matsukata will probably interest students of modern Japanese history, but Part I of this book reads like a graduate thesis, impersonal and inexorable. The occasional anecdote only tantalizes, reminding us that we are reading the words of the man's granddaughter. The work is highly redolent of "official biography," where the lowly samurai climbs to power and glory by dint of Confucian virtue. We fail to catch a glimpse of the man behind the public figure, the man who had eight of his 14 children by mistresses.

An illustrious forbear can dictate a decorous history, partly through the literary dethe reader. Of course the Tokugawa regime was overthrown by imperial loyalists, and the Meiji government went on to establish itself on an equal footing with the West. But it is misleading to write as if it were all inevitable as it was happening. To say that a daimyo's entourage "was approaching the small village of Namamugi when a historic incident took place" reveals an anachronistic sensibility that takes for granted a present that did not exist at the period described.

This example among others is stylistically naive, but the problem of naivet,e runs deeper: according to Haru Reischauer, we should believe that Japan declared war on China in 1894 at her grandfather's insistence that "Japan's honor was staked on guaranteeing Korea's independence." Matsukata claimed this in his self-styled propaganda campaign for foreign nations, true, but it is disingenuous to present it at face value to modern readers, especially when eight years later Japan decided it was necessary to make Korea part of the Japanese empire. Masayoshi Matsukata was a brilliant, dedicated, and undoubtedly honorable man. But he was not the saint this biography portrays him to be, and after many pages of future virtue anticipated, we read of his stint as national leader with less than full conviction.

Perhaps because she does not hold her entrepreneurial grandfather in as much awe as she does her ministerial one, Reischauer's treatment of Ryoichiro Arai is by far the more interesting life story. In the 1870s, its economy thrown out of kilter by a flood of foreign imports, Japan struggled to balance trade by increasing exports. Silk played a major role in setting Japan on the course to becoming the super exporter of the 20th century, and Grandfather Arai played a major role in the silk trade. The two grandfathers' careers might have been juxtaposed more compellingly than through two consecutive chronologies.

It is not fair to criticize a book unduly for what it does not do, but it is valid to ask about the organizing principle dictating the selection of certain events and not others. In Samurai and Silk the promised product is heritage, the organizing device is chronological geneaology, and we can't help but feel that the final result is Haru Reischauer's pedigree.