EXTRA:

Hoshi no Tama

Depictions of kitsune or their possessed victims may feature round or onion-shaped white balls known as hoshi no tama (ほしのたま, star balls). Tales describe these as glowing with kitsunebi. Some stories identify them as magical jewels or pearls. When not in human form or possessing a human, a kitsune keeps the ball in its mouth or carries it on its tail. Jewels are a common symbol of Inari, and representations of sacred Inari foxes without them are rare.

One belief is that when a kitsune changes shape, its hoshi no tama holds a portion of its magical power. Another tradition is that the pearl represents the kitsune's soul; the kitsune will die if separated from it for long. Those who obtain the ball may be able to extract a promise from the kitsune to help them in exchange for its return. For example, a 12th-century tale describes a man using a fox's hoshi no tama to secure a favor:

"Confound you!" snapped the fox. "Give me back my ball!" The man ignored its pleas till finally it said tearfully, "All right, you've got the ball, but you don't know how to keep it. It won't be any good to you. For me, it's a terrible loss. I tell you, if you don't give it back, I'll be your enemy forever. If you do give it back though, I'll stick to you like a protector god."

The fox later saves his life by leading him past a band of armed robbers.