The government upgraded its assessment of the economy after business confidence in Japan improved significantly in the July-September period from the previous quarter.

The Cabinet Office said Friday in a preliminary report that its business survey index jumped to plus 7 in the reporting quarter from minus 21 in the April-June quarter, marking the first entry into positive territory in 11 quarters.

The margin of increase, at 28 percentage points, was the largest since the 31 points marked during a period in 1987, according to the Cabinet Office.