Large Japanese manufacturers indicated their highest level of business optimism in over four years, despite uncertainties brought about from the Iran war. That's according to the Bank of Japan's quarterly Tankan survey, a closely-watched poll that measures business sentiment among domestic companies. The index for business optimism among large Japanese manufacturers increased to 17 for the first quarter of 2026, up from 15 in the previous quarter — per the survey results published April 1 — and against the ...