(Financial Times) -- More gloom descended on Japan's biggest manufacturers this quarter as a strong yen compounded the effects of China's slowdown and Europe's crisis, putting pressure on the central bank to add to last month's surprise monetary stimulus.

The Bank of Japan's Tankan report showed that its key measure of business confidence fell to minus 3 from minus 1 in June, the fourth straight quarter that pessimists outnumbered optimists. That marks the longest string of negative readings since Japan emerged from the global recession in mid-2010.

Just 11 per cent of big manufacturers -- defined as having equity capital of more than Y1bn ($13m) -- said current business conditions were "favourable". Only 9 per cent, down from 11 per cent in the June survey, expected favourable conditions for the remainder of the current fiscal year to March.

The figures suggest that the world's third-largest economy is at risk of lapsing into at least one quarter of contraction, having been boosted by reconstruction-related activities earlier this year. Data last Friday showed that industrial production fell 1.3 per cent from July in August, a bigger fall than in the previous month, while manufacturers predicted a further 2.9 per cent slip in September.

However, those forecasts date from September 10, before anti-Japan demonstrations began in China, prompted by Tokyo's decision to nationalise a chain of islands in the East China Sea also claimed by China and Taiwan.

The dispute "implies a downside risk to production, especially related to autos and electrical equipment", wrote Kyohei Morita, economist at Barclays, in a note to clients.

There are domestic headwinds too. A big programme of eco-car subsidies ran out last month, while a political row over the timing of the next general election has prevented the government from passing a bond-issuance bill needed to finance about 40 per cent of its Y92tn budget for the current fiscal year.

"Given concerns not only about foreign demand but also about domestic demand without policy supports, we expect companies to grow more cautious on production," wrote Naohiko Baba, an economist at Goldman Sachs, in a note to clients.

BoJ governor Masaaki Shirakawa and his colleagues will gather twice to set policy this month, on October 4-5 and October 30. Two weeks ago they took markets by surprise by adding Y10tn ($129bn) to their asset-purchasing programme, the main policy tool with benchmark interest rates near zero, while removing price restrictions on bond buying.

Many analysts expect the bank to hold fire this week, but some have an eye on additional easing at the end of the month, when the bank is expected to lower its growth and price outlook.

Last month the BoJ included the level of the currency in its list of big risks facing the economy.

The yen has gained 48 per cent against the US dollar over the past five years. During the last quarter, the dollar/yen rate averaged 78.64, well below the 82 level exporters say they need to break even.

"The BoJ will need to explore further measures if it wants monetary easing to achieve its unspoken goal of weakening the yen," wrote Izumi Devalier, economist at HSBC in Hong Kong, in a research note last week.