The Brandwater Basin, into which the Boers had retreated from Bethlehem, taking with them Steyn and the Free State Government, which was set up at Fouriesburg, is a semicircle formed by the Witteberg and Roodeberg at the head-waters of two tributaries of the Caledon, the Little Caledon and the Brandwater; the Caledon being the diameter and the mountains the circumference of the area.  The river section of the perimeter lies on the Basuto border, and the mountain section is wild and difficult, there being but four wagon roads into it in nearly seventy-five miles:  at Commando, Slabbert’s, Retief’s, and Naauwpoort Neks.  The passes at Witnek, Nelspoort, and the Golden Gate are scarcely better than rough bridle-paths.

The strength of the enemy holding the Basin and the Neks was about 7,000.  The Boers had indeed established themselves in an apparently strong defensive position, but they had not been there many days before they began to ask each other what was the good of it to them.  They had taken it up against the advice of De Wet, who saw that it was playing the game of Lord Roberts.  They had deprived themselves of their mobility and were confined in a house of detention, where they could do no mischief except to each other.  They realized too late that De Wet was right.  The commandants were at variance and there was indiscipline in the laagers.

De Wet saw that the Brandwater Basin was no place for him.  He was beating his wings in a vacuum, and he resolved to get out of it as soon as possible.  After a Council of War orders to decamp were issued.  The general idea was that a column under De Wet should break out through Slabbert’s Nek and make for Kroonstad, and that Roux should take out another column and march on Bloemfontein, a portion of the force being left behind to guard the passes.

On the night of July 15 De Wet, accompanied by Steyn, who went out to establish yet another seat of government, pulled his column, which included 2,600 burghers and 460 vehicles and was nearly three miles long, out of the Basin through Slabbert’s Nek.  He met with no opposition, and successfully carried out the first episode of the programme.

Hunter at Bethlehem was standing sentry over the northward passes, but want of supplies and deficiency of ammunition prevented him advancing at once on the Basin:  and of the range before him he had no accurate maps and knew less about its topography than an astronomer knows of the Mountains of the Moon.  While formulating a scheme for blocking the passes, De Wet’s sudden outbreak took him by surprise, and he was unable to head the Free State leader, who passed northwards between Bethlehem and Senekal, pursued by Broadwood’s cavalry.  The hounds were on the scent of the first De Wet hunt.

Rundle, who for two months had been painfully, but not with unnecessary deliberation, pushing his force up the right bank of the Caledon, was at first ordered by Hunter to watch Slabbert’s Nek, but on a report that the Boers were about to come out through Commando Nek, he was sent back.  The movement, though justified on the assumption that the report, which came on good authority, was correct, was unfortunate, as it left the key of the gate at Slabbert’s Nek in the enemy’s hands, and allowed De Wet to escape.