▁for ▁more ▁than ▁a ▁year "; ▁according ▁to ▁Admir al ▁Ch ester ▁W . ▁N im itz , ▁later ▁Commander ▁in ▁Chief ▁of ▁the ▁Pacific ▁Fle et , ▁" it ▁would ▁have ▁prolong ed ▁the ▁war ▁another ▁two ▁years ." ▁Nag um o , ▁however , ▁decided ▁to ▁withdraw ▁for ▁several ▁reasons : ▁ ▁American ▁anti - air craft ▁performance ▁had ▁improved ▁consider ably ▁during ▁the ▁second ▁strike , ▁and ▁two ▁third s ▁of ▁Japan ' s ▁losses ▁were ▁in cur red ▁during ▁the ▁second ▁wave . ▁ ▁Nag um o ▁felt ▁if ▁he ▁launched ▁a ▁third ▁strike , ▁he ▁would ▁be ▁risk ing ▁three ▁qu arters ▁of ▁the ▁Com b ined ▁Fle et ' s ▁strength ▁to ▁w ipe ▁out ▁the ▁remaining ▁targets ▁( which ▁included ▁the ▁facilities ) ▁while ▁suffering ▁higher ▁aircraft ▁losses . ▁ ▁The ▁location ▁of ▁the ▁American ▁carri ers ▁remained ▁unknown . ▁In ▁addition , ▁the ▁adm iral ▁was ▁concerned ▁his ▁force ▁was ▁now ▁within ▁range ▁of ▁American ▁land - based ▁bom bers . ▁Nag um o ▁was ▁uncertain ▁whether ▁the ▁U . S . ▁had ▁enough ▁surv iving ▁plan es ▁remaining ▁on ▁Hawai i ▁to ▁launch ▁an ▁attack ▁against ▁his ▁carri ers . ▁ ▁A ▁third ▁wave ▁would ▁have ▁required ▁substantial ▁prepar ation ▁and ▁turn around ▁time , ▁and ▁would ▁have ▁meant ▁returning ▁plan es ▁would ▁have ▁had ▁to ▁land ▁at ▁night . ▁At ▁the ▁time , ▁only ▁the ▁Royal ▁Navy ▁had ▁developed ▁night ▁car rier ▁techniques , ▁so ▁this ▁was ▁a ▁substantial ▁risk . ▁ ▁The