When employing a bag as a shield, what specific filling material maximizes its protective value against edged weapons or blunt force trauma?

When employing a bag as a shield, the specific filling material that maximizes its protective value against both edged weapons and blunt force trauma is a combination of 'soft, energy-absorbing materials layered with dense, impact-resistant items'. Examples of this combination include layering soft clothing or blankets with hardback books or electronics. The soft materials help to disperse the force of a blunt impact, while the dense items provide resistance to penetration from edged weapons. This layered approach provides a more balanced and effective shield than either type of material alone, maximizing its utility in a self-defense situation.