TOKYO, July 1 : Big Japanese manufacturers' sentiment improved in the three months to June to levels unseen since 2018, a closely watched survey showed on Wednesday, a sign the economy was weathering the energy shock from the Middle East conflict for now.The headline index measuring big manufacturers' business sentiment stood at +22 in June, up from +17 in March and exceeded a median market forecast for a reading of +16. It marked the highest level since March 2018.An index gauging big non-manufacturers' mood stood at +37, up from +36 in March. It beat a median market forecast for +35 to mark the highest level since August 1991.The outcome will be among factors the BOJ will scrutinise at its next policy meeting on July 30-31.The BOJ raised interest rates to a 31-year high in June in a landmark step in its policy normalisation, signalling readiness to tighten further as it focuses on taming price pressures from the Iran-war-induced energy shock.