Blocking and Parrying in GURPS, my way.

+Peter V. Dell'Orto, on his very good GURPS blog Dungeon Fantastic, has been posting a couple of his own rules about Parrying and Blocking, especially regarding doing so against very powerful attacks.

Posting all this in the comment section was a bit clunky so I figured I'd just do my own post as a reply/comment since I've been commenting and testing on this.

The BL option for both blocking and parrying is interesting and fast to handle in play I bet but I'm having issues with any "you just can't" or "automatically fail" rules. The more I thought about it, the more I've also been having issues with Parry and Blocking being treated so differently, each with their own rules, and the overall binary feel of attacks and defenses.


For the past week or so, I've been playing with another option to handle all this the way I'd like it, and while it's somewhat cinematic and requires a bit more tracking, the basic concept is there.

The goal:

• Attacks and Defenses have qualities based on how good or bad the rolls are, and this matters.
• The damage roll represents the actual energy put into the attack. A very strong creature doing 7d+2 cr damage can still put very little strength in a blow once in a while (low damage roll). This energy is what matters in damaging shields and weapons when parrying, not the actual BL of the creature (since it's too static).

It goes like this:

• Critical Hits/Misses tables are ignored. Crit Hits do max damage on attacks, min damage on Defenses and normal damage if both are critical successes. Crit Misses means weapon/shield is unready for both Attack and Defense ones. Done.
• All weapons/shields have Base DR/HP. This is based on their Weight, Material, Quality and Reach/Size (ie: (W*M*Q) / R), long reach weapons made of wood having a lower DR/HP than short iron made ones. Not sure about the "realism" of it, but feels right.
• All weapons and shields are treated as Homogeneous.
• Any Parry or Block can cause damage to a weapon or shield. The Base DR is modified as such to give Effective DR = Base DR - (Attack Margin of Success) + (Defense Margin of Success). Damage left over is taken off the parrying weapon or shield. And yes this can get negative DR, which simply adds to the damage taken by the weapon or shield
• Any Attack parried or blocked can cause damage to the weapon used in said attack. Effective DR = Base DR + (Attack Margin of Success) - (Defense Margin of Success). Damage left over is taken off the attacking weapon.
• Armoury skill is critical to ensure "healing" of lost HPs for Shields and Weapons. Didn't expend much on this yet, just applying some form of the first aid rule to it seems easy enough.

In practice, this gives something like this:

• Joe attacks (11 vs 15, MS:4) with an iron broadsword (DR12, HP24) against John who tries to block (9 vs 11, MS:2) with his small wooden shield (DR6, HP30), for 8 cut damage.
• Joe's broad sword DR is 14 (12+4-2), taking no damage from the block.
• John's small wooden shield DR is (6-4+2) 4, taking 6 damage ((4*1.5)).

The actual calculation is easy to make and just requires damage to be rolled no matter what. It adds another layer of HP tracking (for weapons and shield), which is kinda cool in theory I think, but not for everyone in practice even though it's quite easy to do.

What I really like in this is that attacks have qualities (based on the roll, high roll meaning a poorly made attack, low roll meaning a really well executed one) and are no longer binary hit or miss, power (via the damage roll, indicating how much strength you put in the attack) and defenses have qualities as well, going beyond the simple binary system. That's the feeling I really wanted to get, you can get a very good attack technically (attack roll) but not apply much force to it (damage roll) and the opponent can also make a very good defense (defense roll), all varying in quality based on the Margins.


As for Knock-back, it's simple, I apply Knock-back to EVERYTHING cutting/crushing, even if parried or blocked. Since with the above, damage is rolled anyway, it flows nicely and gives a little "dragon-ball" vibe to my otherwise low fantasy/low cinematic setting if there's a "big hitter". A perfect block against a massive giant attack is possible, but you'll still fly a couple yards back because of it, same for parry. Not realistic, but I like the idea.

I've only been doing about a dozen solo test battles with this since last week and overall it performs how I want it too and it gives the feel that I wanted. The main variables to work on still are values to use for materials and quality and that's probably gonna take some time. It also slows down the fights a bit of course, but not that much I feel once you get the hang of it.

Of course, only did this for a purely low fantasy setting and this idea most likely completely implodes on anything >TL3-4 (and probably does anyway no matter the circumstances). 
I won't be using this house rule at first once I run GURPS over roll20 (to avoid overload on players), but I'll most likely go with it once the basics are assimilated.

Also thinking of adding some form of HT check if you're being knock-back as you parry or block an attack, on top of the DX check to stay standing. Maybe HT check, -1 per yard pushed or something, and on fail, limb holding the weapon or shield is crippled or something.

And finally, I'd like to apply this concept for armors as well somehow, therefore adding "damage to armor" as part of the overall combat flow. That'll probably come later though.