A loan guarantee system for smaller firms devised by former Prime Minister Taro Aso helped reduce the number of corporate bankruptcies between April and September by 1.61 percent from a year earlier to 7,736, the first decrease in four years for a fiscal first-half, a credit research agency said Thursday.

Tokyo Shoko Research said the debts left by the failed firms in the first half of fiscal 2009 plunged 71.08 percent to ¥2.50 trillion, in a positive reaction to last year's collapse of Lehman Brothers Japan Inc., the Japanese subsidiary of Lehman Brothers Holdings Inc., and three affiliates.

Lehman Brothers Japan and the three affiliates left ¥4.70 trillion in debts when they went bust in September 2008, with Lehman Brothers Japan accounting for ¥3.43 trillion of the debts.