As its name suggests, the Western Breach is a gap, formed by lava flow,
on the western outer rim of Mount Kilimanjaro

Mount Kilimanjaro

Kilimanjaro, with its three volcanic cones, Kibo, Mawenzi, and Shira, is a dormant volcano in Kilimanjaro National Park, Tanzania and the highest mountain in Africa at above sea level .-Geology:...

's main summit, Kibo.
The Western Breach offers one of the shortest
climbing routes

Mount Kilimanjaro climbing routes

There are several routes by which to reach Kibo, or Uhuru Peak, the highest summit of Mount Kilimanjaro, namely, Marangu, Rongai, Lemosho, Shira, Umbwe and Machame.Annually, approximately 15,000 people attempt to reach the summit of the mountain, of whom 40% do so....

to the summit.
The core of this route, stretching from Arrow Glacier Camp to
Crater Camp, involves several short non-exposed simple scrambling
sections (grade I on the UIAA scale, or equivalently YDS class 2).
It was temporarily closed after a rock slide accident in January 2006
killed three people.
Despite its moderate inherent risks, among experienced climbers
the Western Breach is still a popular ascent route
because it is very direct and more interesting than the two
heavily frequented standard routes on the southeast face of Kibo.