Sunday, 1 September 2024

Weapon Breakage Variant Rules

Weapon Breakage Variant Rules

You probably know that the rules for weapon breakage in GURPS Basic Set (even with expansions from LTC2) aren't perfect. People complain about them a lot. Personally, even though I don't like some parts of them (for example, the fact that they work completely different from rules for Striking at Weapons), I always used them. Pyramid #3-87 has the Broken Blade article that makes the rules for weapon breakage much more involved. While I like that approach, it does require some extra homework (working out breakage thresholds for all the weapons) and extra rolls, which is something many people abhor. A friend approached me and said that his GM is buttmad about the Basic Set weapon breakage rules and that he'd like something like simplified Broken Blade. However, as we were fiddling with those rules, I had another idea - why don't we unify the rules and instead of using different damage rules for different objects we apply Damage to Shields (p. B484) to weapons?

"But Eggplant, weapons do not have a DB!" That's true, so we'll have to come up with something else. Let's call it Parry Threshold, or PT. This parameter should determine how hard it is to parry without damaging your weapon. Thus, it will not be a fixed value intrinstic to a weapon, but a calculated variable. In GURPS Basic Set, the difference is mass defines the chance of breakage. In the Broken Blade, ST of the weapon defines the breakage thresholds. We're going to use both of them, sort of. Let's use the following:

PT = 1 + 1 for each multiple of weight of the parrying weapon by which the parried weapon is heavier + 1 for each full 3 ST by which the attacker is stronger than the defender.

Since I'm too stupid to spell it out in proper English and make it make sense, let me show you some examples:

1. Shortsword (2 lbs) wielded by a fighter with ST 10 parries a long staff (5 lbs) wielded by a fighter with ST 15. PT = 1 + 1 (the staff is twice heavier than the shortsword, but not three times as heavy) + 1 = 3.
2. Thrusting broadsword (3 lbs) wielded by a fighter with ST 12 parries a maul (12 lbs) wielded by a fighter with ST 16. PT = 1 + 3 (the maul is four times heavier than the broadsword) + 1 = 5.
3. Large knife (1 lb) wielded by a fighter with ST 9 parries a main-gauche (1.25 lb) wielded by a fighter with ST 10. PT = 1 + 0 + 0 = 1.

The result of a Parry now varies depending on the defender's margin of success:
MoS 0-PT: The blow strikes the parrying weapon squarely and may damage it, but only if the attack was made with a swung weapon. Apply the attack's damage to the parrying weapon.
MoS > PT: The parrying weapon manages to deflect the attack without the parried weapon damaging the parrying weapon.

As you can see, all this PT stuff only matters when parrying swung attacks. If you're defending against a thrust attack, just skip this part.

In any case, if the attack was made with a swung impaling weapon (e.g. a pick), convert the damage type to crushing. See GURPS Low-Tech Companion 2: Weapons and Warriors, p. 23 for DR and HP values of weapons. As per Damage to Objects (p. B483), if a weapon is reduced to 0 HP or less and fails its HT roll, the weapon breaks or bends, but may remain partially useful (Broken Weapons, p. B485). In this case, the parry still counts. If the weapon is reduced to -1x HP or lower and fails its "death" roll, then it is destroyed, and the parry doesn't count as successful.

Weapon Quality and Composition
When using these rules, some of the effects of weapon quality and composition should be adjusted or elaborated on. HP adjustments from quality do not affect weight.
    Cheap: HT 10. Decrease DR and HP by 20%, rounding down. (Metal weapons DR 6 -> DR 4)
    Fine: HT 13. Increase DR and HP by 20%, rounding down. (Metal weapons DR 6 -> DR 7)
    Very Fine: HT 14. Increase DR and HP by 40%, rounding down. (Metal weapons DR 6 -> DR 8)

Optional Rules

Breaking Weapons on an Attack
A weapon that strikes non-flexible DR 3+ that is higher than the weapon's DR and does not penetrate or cause knockback, may get damaged. In this case, apply the basic damage stopped by the target's DR to the weapon. The weapon's DR protects as normal. Optionally, you may increase the weapon's effective DR for this purpose by +1 for every full 4 pounds of weight. This does apply when the weapon is parried with a MoS 0-PT by a DR 3+ swung weapon, staff, or a two-handed weapon wielded in Defensive Grip.
Flexible weapons made of metal or wood/metal halve their damage and are treated as Diffuse objects. Wood/metal weapons (such as morningstars) are treated as metal weapons with DR 6, not DR 4. Flexible cloth/leather weapons (such as whips) are exempt from this rule - they can strike any DR without damaging themselves.

Clashing Parry
Normally, the defender interposes his weapon with the intent to deflect incoming attack off course. Alternatively, he may make his parry with full force to try and damage the incoming weapon. This is called a Clashing Parry.

Clashing Parry
                            Hard
Default: prerequisite skill Parry-1.
Prerequisite: Melee Weapon skill; cannot exceed prerequisite Parry.

    Instead of merely defelcting the blow, you attempt to damage the attacker's weapon. This is incompatible with Cross Parry and Supported Parry.
    Roll against Clashing Parry to defend with a swung weapon. You cannot retreat. Failure means you're hit; your attacker may choose to hit the original target or your weapon. Success means you parry the blow and may roll against the underlying weapon skill to strike the attacking weapon or shield, modified as follows:
    Modifiers: Against weapons, -5 to parry a Reach C weapon, -4 to parry a Reach 1 weapon, -3 to parry a longer weapon. Against shields, -4 + the shield's DB.
    Success on this skill roll inflicts normal damage against the attacker's weapon or shield. If you are parrying with an impaling weapon, change the damage type to crushing, unless you're parrying a shield, in which case the damage type switch is up to the defender. This works both against thrusting and swinging weapons. Just like when doing a regular parry, if your margin of success is 0-PT against a swung weapon, your weapon is damaged as well. However, in this case, both weapons deal +2 damage or +1 per die, whichever is higher.
    If you are using Fantastic Dungeon Grappling, a successful Clashing Parry that didn't destroy the parried weapon may, if the defender wishes, count as a successful Grabbing Parry (p. FDG3) that applies a 1 CP bind or grapple, if the weapon is capable of being used for grappling. If you parried a shield with an impaling weapon and chose to deal impaling damage, instead of a bind you establish a proper grapple that inflicts CP equal to basic damage. A swung impaling weapon gets stuck.

Cross Parry and Supported Parry
If you're using rules for Cross Parry (p. MA121), then weights of both of your weapons are added together when determining PT. For the purpose of weapon damage and breakage, apply damage to the lightest of the two weapons first, and any excess damage to the heavier one. If both weapons weigh the same, the weapon to be damaged first is determined randomly. This is not compatible with Clashing Parry (see above).

Flexible Weapons
Flexible weapons, such as flails, kusari, whips, nunchaku, etc. are difficult to damage, but also are difficult to use to damage other weapons. When you use a flexible weapon to parry, and the weapon takes damage, treat it as a Diffuse object, not a Homogenous one. If you are using a flexible weapon to perform a Clashing Parry or if Breaking Weapons on an Attack triggers, halve your weapon's damage. In this case, if your weapon is partially composed of wood and metal (as a morningstar, for example), treat your weapon's DR as 6, not 4.

Knocking the Weapon Away
As per Damage to Shields (p. B484), a blow that hits the shield still makes the defender experience knockback. That will not work for weapons, won't it? If you're content with ignoring this, it's okay, but if you want to insert some extra fun, consider the following: If a Parry succeeds by 0-PT, the attacking weapon was a swung weapon, and the parried weapon did not break, the defender must roll against ST+2 at -1 per 2 points of basic damage rolled by the attacker and +2 if the defender is wielding a two-handed weapon (or +3 if in Defensive Grip) or using a Supported Parry with a one-handed weapon. On a failure, the defender drops his weapon, flying 1d-1 yards in a random direction. On success by 0-2, his weapon becomes unready.
If the defender is using a staff or a two-handed weapon in Defensive Grip, and the weapon didn't break on a parry that succeeded by 0-PT, then the defender does suffer knockback.

Examples

Let's make some examples (some damage values may be off for you, because I'm using Reduced Swing Damage):

1. Fighter A (ST 15; 1d+1/1d+2) wields an axe (2d cut; 4 lbs.; DR 4; HP 12). Fighter B (ST 10; 1d-2/1d) wields a shortsword (1d cut; 2 lbs.; DR 6; HP 10). Fighter A swings his axe at fighter B. For fighter B, Parry Threshold is equal to 1 + 1 + 1 = 3. Let's say that his Parry is 11. He rolls his Parry and gets a 10. Margin of Success of 1 falls between 0 and PT 3, so the axe hits the sword squarely. Fighter A rolls 2d damage and gets a 7. Subtracting DR 6, we get 1 point of penetrating damage. Cutting has a x1.5 wounding multiplier even against homogenous objects (this doesn't matter in this case), so the shortsword now has HP 9/10. If using optional rules, fighter B now has to make a roll against ST 10 + 2 - 3 = ST 9. He rolls 11, and his shortsword becomes unready.

2. Fighter A (ST 16; 1d+1/2d-1) wields a thrusting greatsword (2d+2 cut; 7 lbs.; DR 6; HP 15). Fighter B (ST 10; 1d-2/1d) wields a shortsword (1d cut; 2 lbs.; DR 6; HP 10). Fighter A swings his greatsword at fighter B. For fighter B, Parry Threshold is equal to 1 + 2 + 2 = 5. Let's say that his Parry is still 11. He rolls his Parry and gets a 9. MoS still falls within the PT range, so the greatsword hits the shortsword squarely. Fighter A rolls 2d+2 cut and gets a 10. Subtracting DR 6, we get 4 points of penetrating damage. Cutting has a x1.5 wounding multiplier even against homogenous objects, so the shortsword takes 6 points of injury. The shortsword now is at HP 4/10. If using optional rules, fighter B now has to make a roll against ST 10 + 2 - 5 = ST 7. He rolls 11, and his flies 1d-1 yards away in addition to getting damaged.

2.1. Fighter A attacks again, and fighter B suceeds on his parry by, let's say, 3. Fighter A again rolls 2d+2 and gets 12. Subtracting DR 6, the shortsword takes (12 - 6) x 1.5 = 9 points of injury and now is at -5/10. Fighter B roll against HT 12 due to the shortsword being below 0 HP. The shortsword rolls 14, failiing to "stay alive." As per Broken Weapons (p. B485), fighter B rolls 1d and gets a 4. The blade snaps at the hilt, the sword becomes useless, but the parry still counts.

3. Let's reverse the situation from #2. Fighter B attacks fighter A with his shortsword, swinging with All-Out Attack (Strong), because even on the highest damage roll, it wouldn't be possible for him to damage the greatsword. Fighter A has PT = 1 + 0 + 0 = 1. Fighter A has Two-Handed Sword-16 and Parry 12. He decides to perform a Clashing Parry by accepting a -1 to his Parry. He rolls against 11 and gets 10. This is within the PT range, so now he may roll against Two-Handed Sword at -4 (shortsword is a Reach 1 weapon) to damage the incoming blade. He succeeds, so both weapons damage each other, and both weapons deal +2 or +1 per die, whichever is higher, since both weapons are swung. Fighter A rolls 3d cut and gets 14. Fighter B rolls 2d cut (1d + 2 for All-Out Attack (Strong) and +2 for a Clashing Parry) and gets a 8. Thus, the greatsword takes (8 - 6) x 1.5 = 3 injury and now is at HP 12/15. The shortsword takes (14 - 6) x 1.5 = 12 injury and now is at HP -2/10. The shortsword rolls against HT 12 and rolls 12 - it doesn't snap or shatter, but it will have to roll against HT again next time it is used to attack or parry.

4. Fighter A (ST 14; 1d/1d+2) wields a spear (1d+2 imp; 4 lbs.; DR 4; HP 12) stabs Fighter B who is wearing medium plater armor (DR 6). DR 6 is rigid and is higher than DR 4 of the spear, so there is a risk of damaging the weapon. Fighter A rolls 1d+2 imp and gets a 5. This does not penetrate DR 6, and the DR stopped all 5 points of basic damage, so the spear takes 5 - 4 = 1 injury and now is at HP 11/12.

4.1. What if the fighter A rolled 8 damage instead? Then, he'd penetrate DR 6, and the spear would be intact.

5. Fighter A (ST 14; 1d/1d+2) wields a spear (1d+2 imp; 4 lbs.; DR 4; HP 12) stabs Fighter B (ST 16; 1d+1/2d-1) who wields a thrusting greatsword (2d+2 cut; 7 lbs.; DR 6; HP 15). Fighter B has PT of 1 + 0 + 0 = 1. Fighter B has Two-Handed Sword-16 and Parry 12. He decides to perform a Clashing Parry by rolling against Parry 11. He rolls 11. This is within the PT range, but it doesn't matter - the thrusting spear cannot damage the swinging sword that is used to parry it. Now, fighter B rolls against Two-Handed Sword at -3 (spear is a Reach 2 weapon), and succeeds. He rolls 2d+2 cut and gets a 9. The spear takes (9 - 4) x 1.5 = 7 injury. The spear is now at HP 5/12. Close to risking breakage!

Conclusion

I'm content with the result, and I may give these rules a run in an actual game to see how they work. What I like here is that different rules are consolidated, there's no more weapons taking damage one way when used to parry and the other way when attacked - everything works the same way. Parrying was made more interactive and varied, and the distinctions between thrust and swung attacks are more pronounced now. The weapon's DR and HP, and hence the material composition, now matter much more, where as before they were very situational stats. Also, there's something that none of the other weapon breakage rules interact with - armor divisors. Now, if you have an adamantine sword with a (2) armor divisor, you may be able to cut through a weapon that parries it in the same way as you cut through armor, where as before a steel blade that weighs 3 lbs. and an adamantine blade that weighs 3 lbs. would work the same. Of course, if something comes up, I will edit this post to change numbers or add some rules for other edge cases.

5 comments:

  1. How is the Clashing Parry technique significantly different than the Aggressive Parry technique? Both involve attacking the attack, but Aggressive Parry defaults to Parry -4 while Clashing Parry is only -1.

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    Replies
    1. Aggressive Parry defaults to Parry-1, not Parry-4.
      The techniques are very similar, with the main difference being the weapon dealing full damage and the lack of the basic -3 penalty to strike a weapon.

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    2. I was using my files when looking at the Aggressive Parry description, which was taken from 3e and not fully updated for 4e. My error. Love the content, though. You're one of the few blogs I regularly follow.

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    3. Ah, I see.
      Thank you, I appreciate that!

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  2. I have mused about a system that takes skill and margin of success into consideration. Will share here just in case.

    For swung attacks, a weapon parrying another three times or more its own weight may be damaged and break. Note how many times its heavier. The heavier it is, the more you have to succeed at your parry to avoid damaging your weapon:

    3 times heavier: requires MoS of 2 at your parry
    4 times heavier: requires 4
    5 times heavier: 6
    6 times heavier: 8 and so on.

    Modify the required MoS by parrying weapon quality: an extra 2 if cheap, or reduce it by -1 if fine or -2 if very fine.

    No matter how skilled you are, some parries are impossible. If the required margin of success is at least 10, your weapon will break automatically.

    If you succeed at your parry, but not by the required amount, apply the attacking weapon damage to your weapon (I would also add extra injury to it equal to the required Margin of Success.)

    So a Shortsword (2 lbs, DR 6, HP 10), parrying a Great Axe (8 lbs, 1d+5 cut [avg 8 if used by a ST 12 character]), would require a MoS of 4 to avoid damage it. If it did damage the shortsword, it would deal 3 points of injury to it (from it's damage) plus 4 from the MoS required.
    Thus, one or two attacks could disable this shortsword.

    Vs a maul, the shortsword parry would need a MoS of 8, and if it failed, damage would be 1d+6 cr (again, if used by a ST12 character) + 8 injury.

    The MoS injury bonuses would be insubstantial if we are talking about SM+4 giants ducking it out with appropriate sized shortswords and great axes, so there's that.

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