 Early in the new year, the 15th and 18th Brigades relieved the 21st and 25th Brigades around Shaggy Ridge, and planning for a new offensive began.The major Australian attack on Shaggy Ridge – codenamed Operation Cutthroat – was launched by the 18th Brigade on 19–20 January.The 2/4th Field Regiment, which established its guns around the Lake area to the west of the Mosia River, and south of Guy's Post, while stores were brought up to that position by jeep.