the positions had been fortified with machine-gun posts and a modest amount of barbed wire. the defences were impossible to by-pass and had good observation but with so little artillery little advantage could be gained from it. the gap was too wide for the number of defenders, the hills being far enough apart for an attacker to pass between them; only castle hill was behind the other fortified hill tops, providing very little scope for defence in depth. there were several camel tracks through the mirgo pass from black hill and the jerato pass in the assa hills, which gave further opportunities for the italians to exploit their numerical superiority.