▁the ▁city ▁of ▁H iro sh ima , ▁which ▁was ▁the ▁location ▁of ▁the ▁Imperial ▁General ▁Head quarters ▁in ▁the ▁First ▁S ino - J apan ese ▁War ▁and ▁the ▁Ge iy ō ▁Fort ress ▁was ▁constructed ▁to ▁control ▁the ▁Kur ush ima ▁Stra it , ▁a ▁narrow s ▁in ▁the ▁Set o ▁In land ▁Sea ▁between ▁H iro sh ima ▁and ▁Sh ik oku , ▁which ▁blocked ▁the ▁western ▁approaches ▁to ▁K obe ▁and ▁Os aka . ▁ ▁From ▁ 1 9 2 0 , ▁construction ▁began ▁on ▁coast al ▁fort ifications ▁to ▁control ▁the ▁much ▁wider ▁B ung o ▁Channel . ▁Ge iy ō ▁Fort ress ▁was ▁abol ished ▁in ▁ 1 9 2 4 ▁and ▁H iro sh ima ▁Bay ▁Fort ress ▁in ▁ 1 9 2 6 . ▁A ▁second ▁groups ▁of ▁batter ies ▁were ▁completed ▁between ▁ 1 9 3 0 ▁and ▁ 1 9 3 4 . ▁The ▁fort ifications ▁were ▁in ▁five ▁groups : ▁the ▁island ▁of ▁Tak ash ima ▁and ▁Cape ▁Se k iz aki ▁( both ▁in ▁the ▁city ▁of ▁ Ō ita , ▁Cape ▁T sur u ▁( in ▁Sa iki , ▁ Ō ita ), ▁S agan ose ki ▁S agan ose ki , ▁ Ō ita , ▁ ▁and ▁Cape ▁S ada ▁( I k ata , ▁N ish iu wa ▁District , ▁E h ime ). ▁ ▁The ▁largest ▁guns ▁installed ▁were ▁▁ 2 8 - cm ▁how itz ers ▁of ▁the ▁same ▁type ▁which ▁were ▁under ▁during ▁the ▁Rus