Impi warriors were raised from the age of 6. They were trained to outrun a horse, cover about 80 km (50 miles) a day in foot and hide and stalk in the underbrush. They swore loyalty to the king of the Zulu tribe. They were not allowed to marry before they had proved their courage in some way.
Every impi shield was thousand warriors strong and contained warriors from the same age group. Every impi had its own colors in colored shields, headdress and other ornaments. Impi was also accompanied by young boys who carried implements like cooking pots and sleeping mats.
In wartime, warriors painted their upper bodies and faces with chalk and red ochre. Their weapons were shorts spears (assegai), cudgels (knobkerrie) and leather shields. Assegai could be used both in melee and as throwing spears. At the time of Zulu War, king Cetewayo also equipped them with muskets and they also used rifles captured from the British.
Shaka used impis with a modified circling tactics; Impi troops would divide into four groups. Main grtoup (“chest”) would face the enemy, two wings (“horns”) – on two sides of the enemy and then force them towards the center. The fourth party remained as a reserve. During the Zulu War, British commander Lord Chelmsford complained that they did not “fight fair”.
Impi were also famous for their custom “washing of spears (in their enemy’s blood)” in which they cut open the belly of killed (and allegedly sometimes still living) opponents. Supposedly this meant the release of the opponent’s spirit so it could not haunt the killer.
Rudyard Kipling refers to them in his poem Fuzzy-Wuzzy:
We took our chanst among the Khyber 'ills,
The Boers knocked us silly at a mile,
The Burman give us Irriwady Chills,
'An a Zulu Impi dished us up in style.