▁campaign ▁on ▁ 1 3 ▁December ▁ 1 9 1 6 . ▁The ▁British ▁had ▁some ▁ 5 0 , 0 0 0 ▁well - tra ined ▁and ▁well - equ ipped ▁troops : ▁mostly ▁British ▁India ▁troops ▁of ▁the ▁Indian ▁Ex ped ition ary ▁Force ▁D ▁together ▁with ▁the ▁ 1 3 th ▁( West ern ) ▁Division ▁of ▁the ▁British ▁Army ▁forming ▁the ▁Mes op ot am ia ▁Ex ped ition ary ▁Force . ▁The ▁Indian ▁divisions ▁of ▁the ▁Indian ▁III ▁Corps ▁( also ▁called ▁the ▁Tig ris ▁Corps ) ▁included ▁British ▁Army ▁units . ▁The ▁Ott oman ▁forces ▁were ▁smaller , ▁perhaps ▁around ▁ 2 5 , 0 0 0 ▁strong ▁under ▁the ▁overall ▁command ▁of ▁General ▁K hal il ▁P asha . ▁ ▁March ▁on ▁Bag hd ad ▁There ▁were ▁no ▁set back s ▁for ▁the ▁British ▁on ▁this ▁campaign . ▁General ▁Mau de ▁proceeded ▁c aut iously , ▁adv ancing ▁on ▁both ▁sides ▁of ▁the ▁Tig ris ▁River . ▁He ▁earned ▁his ▁nick name ▁System atic ▁Joe . ▁The ▁Ott oman ▁forces ▁cont ested ▁a ▁fort ified ▁place ▁called ▁the ▁Kh ada iri ▁B end ▁which ▁the ▁British ▁captured ▁after ▁two ▁weeks ▁of ▁sie ge ▁work ▁( 6 ▁January ▁to ▁ 1 9 ▁January ▁ 1 9 1 7 ). ▁The ▁British ▁then ▁had ▁to ▁force ▁the ▁Ott oman ▁forces ▁out ▁of ▁a ▁strong ▁def ensive ▁line ▁along ▁the ▁H ai ▁River . ▁This ▁took ▁them ▁two ▁more ▁weeks ▁( from ▁ 2 5 ▁January ▁till ▁ 4