Jack’s shuriken can’t pierce armor

‘Miyuki!’ Jack cried in despair, too far away to prevent her death.

Then he spotted a familiar glint of steel flash through the air. Sayomi flinched as the shuriken Jack had given Miyuki embedded itself in her upper chest. But Sayomi’s armour prevented the throwing star from penetrating deeply. She recovered quickly from the attack and swung the naginata’s blade down on to Miyuki.
- Young Samurai: The Ring of Fire