tokyo dec 8 reuters  japanese manufacturers business confidence index rose to a fourmonth high in december as supply constraints began to ease the reuters tankan showed offering policymakers some hope the economy was headed for a moderate recovery the reuters tankan index readings are derived by subtracting the percentage of respondents who say conditions are poor from those who say they are good a negative reading means that pessimists outnumber optimists following is a table of indexes for key sectors and a comparison with the bank of japans quarterly tankan survey