What made the fight against the mountaineers more difficult?

-The terrain is more difficult to fight in the mountains than on the plain.
-The remoteness of the Caucasus from the center of the country, there was no railway there during Shamil’s time.
-Lack of a noticeable difference in weapons, machine guns and airplanes have not yet been invented (or, for example, poisonous gases, which allowed the Italians in 1936 to quickly turn the tide of the war with Ethiopia).
– Help the mountaineers from outside (Turkey).