Distinctions between the fantasy realm and the modern realm bring on several new rules. These new rules are explained here to be appended to the basic rules found in Cyno's Role-Play rule book.
This rule applies when a character is wearing some sort of armor. Each weapon has a penetration rating and each armor has two penetration ratings. For the armor, one penetration rating is called Vibration Penetration (VP) and the other penetration rating is called Total Penetration (TP).
Vibration penetration means that the attack has penetrated the armor, hurting the armor wearer through blunt vibration or blunt shock. However, the weapon has not penetrated the armor, and it did not come in contact with the armor wearer. Total penetration, on the other hand, means that the weapon has penetrated (pierced) the armor and it has came in contact with the armor wearer.
To determine whether the attack damage has totally penetrated the armor, take the weapon's penetration rating and subtract the armor TP rating. The result is the bonus/penalty needed to be applied to the roll to strike. If the result of the strike roll after applying the bonus/penalty is over 10, than the attacker's weapon pierced the armor.
For example, assume the attacker is using a two-handed sword (penetration rating of 14), and the defender is wearing plate mail armor. The attacker's strike roll is 15, hitting the defender. The plate mail armor has TP rating of 20. Therefore, 14 - 20 = -6. This means that the attacker must subtract 6 from the strike roll. The result is 9, meaning the attack has not totally penetrated the plate mail armor.
If the attack hit the defender, but did not totally penetrate the armor, then the same calculation must be done with the vibration penetration rating. The calculation result is the bonus/penalty needed to be applied to the same roll to strike value. If the result of the strike roll after applying the bonus/penalty is over 10, than the attacker's weapon causes blunt damage to the defender the armor.
Continue from the same example above, the attack failed to pierce the armor, therefore, you need to determine whether it causes blunt damage through vibration. The plate mail armor has a VP rating of 18. Therefore, 14 - 18 = -4. So the attacker subtracts 4 from the strike roll. The result is 11. The value is more than 10, so the defender takes damage from the blunt strike force.
Vibration penetration does only half (rounded down) of the damage, while total penetration does the full damage. Roll damage (based on weapon's damage rating) only after determining whether penetration has occurred.