 The task allocated to the British Commonwealth force was to take these positions with the intention of advancing the line from the southern bank of the Imjin to a line of hills to the north , in total an objective that stretched more than 15 kilometres ( 9 @.@ 3 mi ) . The primary objectives of the advance would be the capture of Kowang @-@ San ( Hill 355 ) and Maryang San ( Hill 317 ) and the task of taking these positions was allocated to the 28th British Commonwealth Brigade , with this formation bearing the brunt of the fighting . <unk> planned on capturing the Jamestown Line in three phases . In the first phase , scheduled for 3 October , the 28th Brigade would take Hill 355 in the east @-@ central sector . During the second phase , on 4 October , the 25th Brigade would assault the two Hill 187 features and the south @-@ western ridge running to the <unk> River . Lastly during the third phase , scheduled for 5 October , the 28th Brigade would capture Hills 217 and 317 . As such , the bulk of the division 's strength would be concentrated on the right flank , to be held by the 28th Brigade ; meanwhile , the 25th Brigade would hold the left flank and the 29th Brigade would be held in reserve while providing a battalion to each of the other brigades as reinforcements . 
