Naruto: Shippūden

Choza Akimichi:
The mark on the right is the Akimichi clan's symbol, see? Let's see...the centre one's the Nara clan's, and the left is the Yamanaka's. We've each mastered some very rare secret ninja techniques. They have a special relationship; our three clans have teamed up and worked together for generations. To strengthen our unity, it's tradition that the Sarutobi gave us gifts of special earrings that we present to each generation when they swear their oaths. (...) It's so we never forget the oath we take. The earring's always there, whispering it into our ear. You're going to have to get pierced too someday. You'll wear my earring from the day you become a genin to the day you become a chuunin.