Somali shields (Gashaan) typically have two variants, a larger and dominant variant that measures anywhere from ~30 to 60 cm in diameter. This larger variant is carried with the forearm and is sometimes secured with lanyards. This was the far more common and dominant variant of gashaan used both in Somali warfare and ceremony.

The smaller variant, which this question concerns, is mostly around ~10-25 cm in diameter. As such, it is a hand-held shield. It's defensive uses was centered around fist movements, and the shield can be used to deliver a blow to the head against an opponent or to blind an opponent in close quarters, with the former only being effective depending on the strength and bulk of the hide used to make the shield. Its defensive uses were, as shields are supposed to do, block - the difference being the the smaller gashaan was better suited and made for shielding against projectiles. Typically, projectiles would be either the Somali javelin or spear, with the javelin being a long to mid range projectile, and the avg Somali spear (~6 ft) long to short ranged. The larger variant shields would only serve to handicap the experienced Somali warrior from seeing incoming projectiles that he would have seen had he been wielding the shorter variant shield. In this respect, only an experienced warrior would see the smaller variant superior in this regard, with the given acumen and experience of shield-blocking many far and mid ranged projectiles garnered from the many battles, skirmishes, and hostile encounters a Somali clansman would have faced in early periods. The defensive stancing for the smaller variant gashaan against incoming projectiles was to only hold the shield at arm's length, with mobility best serving on the warriors side.

It should be noted that this smaller variant gashaan is most common amongst Somali clans that inhabit the southern coastal regions, most notably the southern Abgaal, Ajuraan, and Mursade Hawiye sub-clans and the Biimaal Dir subclan. It was also the dominant gashaan variant when it came to re-enactments and ceremony during the 20th century in greater Somalia, and maintains such status in contemporary periods amongst Somalis worldwide with its widespread use in Somali marriages, parades, movies, and the like.