TOKYO, Oct 2 (Reuters) - Japanese big manufacturers' business confidence improved in September from three months ago, the Bank of Japan's closely watched quarterly "tankan" survey showed on Monday, underscoring the central bank's rosy economic view.
The headline index for big manufacturers' sentiment stood at plus 22 in September, and is expected to fall to plus 19 over the next three months, the tankan showed.
The reading compared with plus 17 seen in the previous survey in June, which was at its highest level in more than three years, and a median market forecast of plus 18.
The tankan's sentiment indexes are derived by subtracting the number of respondents who say conditions are poor from those who say they are good. A positive reading means optimists outnumber pessimists. (Reporting by Leika Kihara and Tetsushi Kajimoto; Editing by Chang-Ran Kim & Shri Navaratnam)