Umbwe route starts at the gate with the same name, although it is not technical but it very steep and at some parts very difficult to climb if you have not enough strength and experience in trekking rough terrains. It joins Machame route at Barranco camp, but the path before it is pretty exposed, and that is why Umbwe is considered the most difficult route on the Kilimanjaro.
We absolutely do not recommend it to the people without experience and lesser physical strength. It can be climbed in 5, 6 or 7 days, but do note that shortest plan does not offer acclimatization day to accommodate the high altitude conditions. Descend is at Mweka Gate.