Magatama

The Magatama is a mysterious object given to Phoenix by his assistant Maya during Ace Attorney 2 and is subsequently kept by Phoenix for the rest of the series.

Shaped like the number 9, when charged with spiritual energy the Magatama has the special ability to allow it's possessor to view Psyche-Locks, which appear when someone is hiding information from the user. After presenting the Magatama to someone, the user can proceed to break their Psyche-Locks with evidence. Once all of someone's Psyche-Locks are broken, they will finally admit the truth of what they know about the subject in question. Magatamas are often worn by members of the Fey family, although unless charged with spiritual energy, they seem to have no functional purpose.