In 1819 Shaka decided to challenge the powerful Ndwandwe chieftain Zwide, and he prepared for battle by establishing a network of spies so efficient that Shaka knew every move of Zwide’s almost before he made them. Zwide was persuaded that he would be able to catch Shaka’s regiments “sleeping” but as soon as his army set off, Shaka’s subjects – men, women and children – were alerted and all set off up the Mtonjaneni heights carrying what corn they could, and having destroyed what they could not. They continued their “retreat” past Nkandla and finally over the Thukela River. Zwide’s army thus found no food on their long march and arrived at the Mhlatuze River (as Shaka had planned) tired and hungry. After two more days of fierce fighting – the corpses piled up on the banks of the river made it almost impossible to maintain a foothold – Zwide’s 20 000-strong force were soundly defeated and broke for home, giving the battle its name as they resembled cockroaches running up the slopes with their shields on their backs.