Yamato Spear

Yamato Spear (Yamato Supia) is Yamato Man's Special Weapon. Mega Man sends spearheads. When rapid-firing, they make a v-shape.

Robot Master And Bosses Weak Against Yamato Spear

 * Knight Man: Mega Man 6
 * 'Rounder 2 : Mega Man 6
 * Power Piston: Mega Man 6
 * Mechazaurus: Mega Man 6
 * Tank-CS2: Mega Man 6

Triva
It should be noted that this is the only weapon that can sneak past Knight Man's shield.