In a country where full-time workers still enjoy strong legal protections, deflation has been blamed for growing social inequality, as companies supplement their expensive permanent workforces with low-paid and easy-to-fire temps.
It has also helped lift the yen to a 15-year high against the dollar - hurting exporters such as Toyota and Panasonic and putting even more pressure on the domestic economy. "The yen's strength slows growth and cuts import prices, making deflation worse," says Richard Jerram of Macquarie Research.
Not all Japanese suffered deflation equally. Lower prices mean salaried workers can stretch pay further (though bonuses, which can account for more than a quarter of annual income, have often withered).
Old people on fixed incomes have done well, too - a situation that some believe makes the government less motivated to tackle the problem. More than 20 per cent of Japanese are past retirement age, and thanks to a voting system that favours depopulated rural areas, their votes carry even more weight.
"At the centre of the problem is the rule [of Japan] by the elderly," says Nobuo Ikeda, an economist and blogger.
Japan can blame part of its troubles on the global forces that have, for a generation, kept inflation mild in other countries - such as the entry of China, India and other low-wage producers into the world trade system. But the impact has been compounded by domestic strains: a flat-to-shrinking population and lingering over-capacity from its 1980s asset bubble.
Such "structural" causes are often cited by the Bank of Japan in response to critics - and there are many - who say it has done too little to combat price declines. The central bank pioneered unorthodox "quantitative" easing in 2001 when it began plying commercial lenders with ultra-cheap cash, after it had cut short-term interest rates to zero with little effect.
In the wake of the great recession, however, the BoJ has looked timid beside the US Federal Reserve and Bank of England, which have taken quantitative easing further by printing cash to buy up government debt. The BoJ has expanded its balance sheet slightly, but its efforts remain focused on trying to induce commercial banks to lend - even though defensive-minded companies hardly seem desperate to borrow.
For industry, coping with deflation has meant slashing costs and, in many cases, moving production abroad. Nissan is selling Thai-made cars in Japan, while Yamaha, the musical instrument maker, began importing pianos this year. The low-end models, made at a Yamaha factory in Indonesia, sell for about 20 per cent less than the company's cheapest made-in-Japan versions.
According to the company, "consumers are coming to accept a wider range of products made outside Japan".
The few businesses that have prospered from deflation have certain traits in common, such as global supply chains and management that is relentless about squeezing out costs.
Uniqlo, the clothing-store chain, has conquered Japan with its Y2,000 ($24) fleece jumpers and made its founder, Tadashi Yanai, the country's richest man. Mr Yanai now wants to grow Uniqlo and its parent, Fast Retailing, into the world's dominant clothing company.
For investors, deflation's power to destroy the weak makes it all the more important to choose carefully. "For every 100 Japanese companies there will only be one with Uniqlo's capabilities," says Kazuyo Katsuma, a businesswoman and author. "The other, regular companies won't be able to handle the price competition, and will be forced to restructure or fold."