After some skirmishes, the Tibetans crossed the Tuko La pass some two miles from Gnathong. Quickly they started building a wall on the ridge of the pass, some three or four feet high and almost four miles wide. Colonel Graham attacked the Tibetan positions around 8 a.m. with three columns. He led the left column, which attacked the blockhouse that guarded the Tuko La pass. Lieutenant-Colonel Bromhead commanded the centre column that was to advance up the main road to Tuko La. The right column, commanded by Major Craigie-Halkett, was to occupy the saddle-back north east of Woodcock hill and hold the Tibetans' left. Around 9:30 am the attack was opened with the bombardment of the Tibetan left flank by the artillery of the British right. At 10:30 the other two British columns were in contact with the Tibetans, and the British penetrated the defences and captured the Tuko La pass, after which the Tibetans retreated through the Nim La pass. After securing his flanks, Colonel Graham moved to attack the Tibetans at the Jelep La pass which was attacked at 2:00 pm and captured shortly afterwards. The next day the pursuit continued and by 4:00 pm the British had occupied Rinchingong.