When new Japanese Prime Minister Junichiro Koizumi put a limit on government bond issuance, he hoped to rein in the country's soaring public debt. He may also have been reacting to its bestseller lists. Ever since author Main Kohda published a wildly successful thriller on the topic last fall, Japan's public debt - the OECD's highest, at 130 percent of GDP - has become an unlikely staple of TV talk shows.

In Kohda's simply titled Nihon Kokusai (Japanese Government Bonds), a group of fixed-income traders decides to boycott a government bond auction, resulting in soaring interest rates, a collapsing yen and an anxious call to Tokyo from the White House, which fears that the Japanese will sell their vast holdings of U.S. Treasuries to cover mounting debts. Kohda, 50, admits her book is sensational but asserts that the disastrous chain of events could occur. She says that Japan's biggest banks and brokerage firms, which buy most of the country's bonds, have an unwritten agreement with the government to keep yields low, in return for other favors. If a handful of firms declined to participate, the whole process would unravel.

Most experts might dispute her charges, but Kohda is no outsider to the bond world. Her r,sum, includes more than a decade of work for two former U.S. banks, Continental Illinois National, where she was a forex trader, and Bankers Trust, where she sold foreign bonds to Japanese institutions.

Kohda began writing in 1993 after a serious illness and has produced a string of novels that blend crime, sex and disturbing insights about Japan's financial system. Her latest effort sold 135,000 hardback copies in six months and has landed her more than 20 TV talk show appearances. Kohda says her ambition is to make readers "understand that the way they see Japan isn't how the world sees it." Her audience seems to be catching on.