▁York town , ▁which ▁was ▁later ▁s unk ▁by ▁a ▁Japanese ▁sub marine ▁I - 1 6 8 . ▁In ▁response , ▁US ▁launched ▁a ▁strike ▁against ▁H iry ū ▁and ▁s ank ▁her . ▁That ▁day ▁the ▁Japanese ▁lost ▁four ▁aircraft ▁carri ers ▁and ▁much ▁of ▁their ▁experienced ▁air cre w . ▁ ▁Battle ▁of ▁the ▁Philipp ine ▁Sea ▁ ▁The ▁US ▁Navy ' s ▁attack ▁on ▁the ▁Japanese ▁base ▁at ▁Tru k ▁( Ch u uk ) ▁on ▁ 1 7 ▁February ▁ 1 9 4 4 ▁( Operation ▁H ail stone ) ▁surprised ▁the ▁Japanese ▁military . ▁In ▁response , ▁the ▁Japanese ▁Navy ▁ordered ▁all ▁of ▁the ▁ 6 1 st ▁Air ▁Fl ot illa ▁to ▁the ▁Marian as ▁Islands . ▁Its ▁Number ▁ 2 6 1 ▁Ka ig un ▁K ō k ū ta i ▁( fig h ter ) ▁advanced ▁to ▁Sa ip an ▁circa ▁ 1 9 – 2 4 ▁February ▁ 1 9 4 4 , ▁but ▁attr ition ▁in ▁air ▁comb ats ▁and ▁ill ness ▁weak ened ▁the ▁unit ▁greatly ▁and ▁it ▁played ▁only ▁a ▁minor ▁role ▁in ▁the ▁Battle ▁of ▁the ▁Philipp ine ▁Sea . ▁Element s ▁of ▁No . ▁ 2 6 3 ▁Ka ig un ▁K ō k ū ta i ▁( fig h ter ) ▁of ▁the ▁ 6 1 st ▁Air ▁Fl ot illa ▁were ▁station ed ▁on ▁Gu am ▁from ▁ 1 5 ▁June ▁ 1 9 4 4 ▁and ▁participated ▁in ▁the ▁battle . ▁ ▁Battle ▁of ▁Ley