Umutwe w'icyuma ugizwe ahanini n'ibice bitatu: uturindantoki tw'amashami, umuyoboro utwara amashanyarazi (umuyoboro w'ingufu), n'agasanduku gakingira ubushyuhe; impande z'inkokora zigaragara muri sitasiyo zo guhinduranya ibikoresho n'udusanduku tw'ingufu mu by'ukuri zingana n'amaboko akingira ubushyuhe. Birumvikana ko abakora ibikoresho bazaba bafite umuyoboro utwara amashanyarazi uhuye n'umutwe umeze nk'inkokora; ariko uturindantoki tw'amashami muri rusange ntabwo ari twiza (ntibyemewe), ugomba kugura agakoresho kuzuye k'icyuma mu gihe cyo kubaka (abakora utwo dutambaro bamwe na bamwe batanga uturindantoki tw'amashami), nyuma yo gukora uturindantoki tw'amashami, shyiramo umuyoboro utwara amashanyarazi (witondere urwego rutwara amashanyarazi, uruganda rukora ibikoresho rusange ruzaba rufite agakoresho gafata amashanyarazi), hanyuma ushyire ku mutwe umeze nk'inkokora.
