Ka dib markii ay ku fashilantay Badda Koonfur Bari Aasiya bilihii ka dambeeyay Pearl Harbor, Japan waxay dooneysay inay sii ballaariso dhulkeeda, iyadoo la wareegtay Jasiiradaha Solomon iyo qaybo ka mid ah New Guinea. Bishii Maajo 1942, ciidamada Mareykanka iyo kuwa Australia ayaa ka adkaaday Japan dagaalkii Badda Coral, taasoo keentay in Japan ay duulaan dhulka ah ku qaadaan
waxay ku taalaa jasiirada New Guinea. Japan waxay sidoo kale weerar ku qaaday Jasiirada Midway oo ay Mareykanku lahaayeen iyagoo doonaya inay gacanta ku dhigaan jasiirad si istiraatiiji ah u fadhida isla markaana ay u burburiyaan ciidamada Mareykanka ee ku sugan Badweynta Pacific. Caawimadii mashruuca Magic cryptanalysis, Admiral Chester Nimitz wuxuu hogaamiyay ciidan Mareykan ah oo ka adkaaday ciidanka badda Japan dagaalkii Midway. Dagaalkii Midway wuxuu sababay khasaaraha afarta diyaaradood ee muhiimka ah ee maraakiibta Japan, dagaalka ayaa calaamadeeyay isbadal weyn oo nasiib ah Dagaalkii Baasifiga. Bishii Agoosto 1942, Mareykanka wuxuu bilaabay duulaankii jasiiradda Guadalcanal ee Koonfurta Baasifigga ee ay haysteen Japan ee Jasiiradaha Solomon; Ciidamada Japan iyo kuwa Mareykanka ayaa ku tartamay gacan ku haynta Guadalcanal ilaa Febraayo 1943. Dagaalkii Guadalcanal ka dib, Maraykanku wuxuu qaatay istaraatiijiyad jasiirad ka jasiirad ah si uu uga fogaado ciidamada Japan ee ku dhuumaaleysan jiray. Horraantii 1944, ciidamada xulufada waxay la wareegeen gacan ku haynta inta badan New Guinea waxayna ka soo degeen jasiirada New Britain.