Sundial

Around the time the Toa were searching for their Kanohi, Onu-Matoran miners discovered a large sundial buried in a seemingly impenetrable rock layer in an Onu-Wahi mine. While exploring, Takua joined the prospectors examining the sundial. One of them asked him to deliver a message to an astrologer he knew. The astrologer determined that when the shadow from the sundial's gnomon hit the four o'clock position, something would happen. She then gave Takua a gnomon she had found some time ago, which she suspected went with the sundial. Sure enough, the gnomon fit, and when Takua shined a lightstone on it so that it indicated four o'clock, the sundial opened, revealing a passage through the rock layer with a gold Kanohi Hau at the bottom. The Hau later disappeared.

Much later, after the Matoran had returned to Metru Nui and the Toa Nuva were following a list of tasks needed to restore the universe to working order, a strange voice told Lewa to return to Mata Nui and retrieve the sundial, which he did. The sundial was then shrunk, and given to Takanuva by Toa Krakua. Its purpose was to locate the legendary Codrex.