Ngakhale tonse tikudziwa nkhungu ya njerwa yosayaka, anthu ambiri sadziwa kupanga nkhungu yamtunduwu. Ndiroleni ndikudziwitseni. Choyamba, pali mitundu yambiri ya nkhungu zamakina a njerwa, monga nkhungu za njerwa zopanda kanthu, nkhungu zokhazikika za njerwa, nkhungu za njerwa zamitundu ndi nkhungu zogonana amuna kapena akazi okhaokha. Kuchokera kuzinthu zakuthupi, pali mitundu itatu. Yoyamba ndi nkhungu yopangidwa ndi chitsulo wamba, yomwe imagawidwa kukhala nkhungu yapamwamba komanso yotsika, Yachiwiri imapangidwa ndi No. Chachitatu ndi nkhungu ya zinc carbon, yomwe ili yofanana ndi No. 65 manganese zitsulo. Pamene chizindikiro cha manganese chikukwera, mphamvu yolimbana ndi chibale imakhala yovuta kwambiri, komanso imakhala yosavuta kukhala yolimba. Ichi ndichifukwa chake nkhungu nthawi zambiri imakhala yabwino kwambiri pamene manganese ali ndi zaka 65 zokha. Ziribe kanthu kuti chizindikirocho ndi chokwera bwanji, chimakhala ndi mphamvu, koma n'chosavuta kusweka. Ngati chizindikirocho chili chochepa, chilibe mphamvu komanso sichimva kuvala. Ichi ndi chiyambi chachidule cha nkhungu.