I't's been Japan's best-known but least-spoken shame.
At home, it's discussed only in whispers.
Abroad, it's been confessed behind closed doors - and later denied.
The taboo: more than $1 trillion in bank lending gone bad.
Although the rotten debt weighs on worldwide markets and economies, it's always been as much a problem of politicians as of bank ledgers.
Japanese politicians in the 1980s winked at bankers rollicking in a spree of inane lending. And as the loans began to sour in the 1990s, the politicians allowed bureaucrats to do some fancy bookkeeping, spreading the debt onto the books of healthy banks.
But the bad debt didn't evaporate. It grew.
Tokyo in recent years has repeatedly tried to hide or underplay this "Mt. Fuji" of debt. A ruling party "in denial," analysts say, failed to initiate the bold, creative steps necessary to reverse the problem.
"Japan's government has been run by ... elderly men whose motto is, 'Never do anything for the first time,' " says Robert Dunn, an economics professor at George Washington University in Washington. "I get the feeling they are frozen in amber."
The attempt to publicly ignore looming bad debt recalls the collapse of hundreds of savings-and-loan associations during the last decade in the United States.
As with the S&L crisis, Japan's dithering threatens US economic growth and financial stability. A daisy chain of Japanese bank failures would intensify a global credit crunch.
For months, Washington has called on Japan to adopt its formula for ending its banking debacle.
The scheme is simple to describe, but politically excruciating to execute: Close or sell off insolvent institutions; protect depositors with taxpayer money; punish executives guilty of fraud; and launch a stiffer regulatory regime.
In the United States, the tab was $166 billion, the biggest federal bailout of an industry ever.
Japan's final bill will be many times higher, with political costs to match.
The ruling Liberal Democratic Party must stand up to the all-powerful Finance Ministry and require sacrifice from some of its pillar constituencies, especially farmers.
"Japan's political process is one of incrementalism," says I.M. "Mac" Destler, an economist at the University of Maryland. "You have the combination of a weak political leadership and a very strong Finance Ministry, so it's a tough one for the Japanese."
In recent days Japan has made progress. The upper house of parliament has agreed on the basic structure for a bank-sector shake-up.
Moreover, opposition parties have reversed a longstanding position and agreed to use more than $500 billion in taxpayers' funds for a sweeping overhaul.
But analysts note that these agreements mark only a beginning, and executing the plan might prove even more nettlesome than creating it.