Even with increased output ⇒ of Manchuria + Korea + all its other territories → Japan could not challenge power of US outright. Sept 1940 → Japan signed Tripartite Pact → which made it an ally of Germany and Italy.
- pact was meant to be insurance against US intervention.
Japanese commanders → also decided → they needed to deliver quick knockout blow to US → from which latter would take time to recover. → in that time → Japan would be able to conquer new territories + build up its economic resources + match US power.
Admiral Yamamoto Isoroku → devised pre-emptive skill → against US. Strategy → targeted powerful US pacific fleet base → at pearl harbour → which protected US + other western interests in Asia.
Morning of 7th Dec → 300 planes → took off from Japanese aircraft carriers → launch attack on Pearl harbour.
- attack caused widespread destruction
- Japan failed to destroy American Repair shops + fuel oil tanks + other crucial naval installations.
All 3 US pacific fleet’s aircraft carriers → escaped unscathed → as they were not present at Pearl harbour. → with this attack → US declared war on Japan → triggering outbreak of WW2 in Asia-Pacific.