The Tanzanians decided shortly thereafter to attack the Ugandan capital, Kampala, and the 205th Brigade was detailed in early March to be sent north from Masaka and then west of the city.

Ugandan President Idi Amin declared over radio that his forces were about to surround the TPDF, prompting Tanzanian commanders to dispatch the 205th Brigade to deal with the Uganda Army's Tiger Regiment in Mubende.

In 1971 Idi Amin launched a military coup that overthrew the President of Uganda, Milton Obote, precipitating a deterioration of relations with the neighbouring state of Tanzania.

However, Ugandan rebel forces did not have the strength to defeat the Libyan units coming to Amin's aid, so Nyerere decided to use the TPDF to take the capital.

[6] As part of the plan to take Kampala, the TPDF's 205th Brigade was to advance on Mpigi in early March and then to Mityana and launch an attack on the capital from there.

[8] The 205th Brigade encountered the entrenched Tiger Regiment in Sembabule, along with several soldiers and recruits from the Uganda Army's School of Infantry in Kabamba.

[11] The 205th Brigade, a new and inexperienced unit,[12] was unable to make significant progress in taking the town, as positions it seized were frequently recaptured by the Ugandans.

Tanzanian soldiers became discouraged by the sight of the decapitated bodies of their comrades in trenches, and morale declined to a point where units as large as battalions were retreating upon being subject to fire from the Ugandans.

[8] Kimario was picked up by plane from Zanzibar and flown to northern Tanzania to disembark;[14] he eventually arrived at the battle finding the 205th Brigade disorganised, morale low, and that about 20 Tanzanian soldiers had been killed.