Luck (and Unluck) Fighting Fantasy style (homebrew)

[Rabenrecht]

To represent extraordinary luck or unluck one can take the Luck and Unlucky traits. Although I'm not really a fan of resource based abilities that recharge based on real-world game time, those two traits do a fine job.

But in preparation for Fantasy game based on the Setting of the Fighting Fantasy series of gamebooks (for which, iirc, SJG-Steve Jackson wrote one book: Scorpion Swamp) These two traits are not enough.

In the world of Titan, the Setting for the vast majority of Fighting Fantasy books, Luck is an essential and tangible part of the world.
Luck is also one of the three main stats your character has in all of the books. The mechanic, while simple, is quite clever.

Because it is so important I want to create something like it in GURPS.

Here is how Luck in Fighting Fantasy works:
The PC has a numerical "Luck" stat.
In certain important situation where the outcome lies outside the skill of the character but in the realm of what one could call luck, the character is forced to make a Test of Luck. This is the passive part of Luck.
Luck can also be used actively: in that the character chooses to rely on their luck. The General application of that is in combat where you can score a lucky hit or turn a normal hit of the enemy into a graze. But there are other, non-combat, applications (like gambling). This use, again, needs a Test of Luck.

For Testing your Luck, you roll 2d6. If the result is equal or less your Luck score, you are lucky. Conversely, if the result is greater than your Luck score, you are unlucky. That is, luck is often binary: if you rely on your luck but fail the Test of Luck, the result is often worse then if you didn't tried your luck.
Your Luck is also limited: whenever you perform a Test of Luck, the Luck score is reduced by one (after the test).

You can also gain or lose luck in other circumstances: if you through your actions create your own luck you might gain luck points; conversely if you do something with spectacular bad results you might lose luck. Curses can attack you luck and Blessings can restore it.

For my GURPS Fighting Fantasy campaign I have the following in mind, which combines the ideas from Fighting Fantasy with a more traditional “Bennies”/”Fate Point”/”Fortune Points” approach:
Each PC has a Luck score*. The base score would be 8 or 9 (haven’t decided yet).
In addition, at the start of an adventure (one “story arc” you could say – but there is no hard definition), each player receives 4 Luck Points, ideally represent by physical tokens.
There is also a maximum number of Luck Points a player can have at any point: Luck Score / 2 + 2
A Test of Luck is like a normal attribute test with the Luck score as the attribute. The player receives a bonus equal to the number of Luck Point they have. Each Test of Luck costs the player one Luck Point (paid after the Test). I’m not sure if this roll should be possible to crit in either direction. The effect for a critical success is quite easy: the Test doesn’t cost a Luck Point. But I have no idea for the effects of a critical failure. Failing a Luck Test already results in something bad most of the time.
If a player has no Luck Points left, they can’t actively Test their Luck. If they are forced to a Test of Luck, the test automatically fails.

So far I’ve only worked out the effects of actively Testing your Luck in combat:
Offensive use of Luck: after a successful attack roll if the target failed to defend (whether because of a failed roll or because no defence was possible) a successful Test of Luck can turn the success into a critical success. Failing the Test of Luck turns your success into a regular failure.
Defensive use of Luck: after being successfully attacked and failed to defend (again, whether because of a failed roll or because no defence was possible; but: you can’t Test your Luck against a critical hit) a successful Test of Luck turns the failure into a success. Failing the Test of Luck means that you have been critically hit.
For active non-combat uses of Luck, I’m not sure what kind of predefined effects should exist, if any.
For any non-combat use of Luck, whether active or passive (forced), the simple principle that a successful Test of Luck should result in something quite positive while a failed Test should result in something negative should hold true.
Passive Test of Luck would be called by the GM more or less in the same fashion as detailed above (It is author fiat in the Fighting Fantasy books, so I have no problem with it being GM fiat in GURPS).
The GM can also award Luck Points or impose a loss of Luck Points, again in the same fashion as in the Fighting Fantasy books detailed above. For rewarding Luck points, the maximum number of Luck points comes into play. The loss of Luck Points on the other hand can result in the player loosing Luck Points they don’t have anymore. In this case for each point of Luck the player would lose their characters Luck Score is reduced by one. If the player receives Luck Points later on, they can choose to “repair” their damaged Luck Score on a 1-by-1 basis.

For character creation and advancement, the Luck Score cannot be increased or decreased like other attributes. Instead one could buy the “Lucky” advantage or the “Unlucky” disadvantage. Those traits of course replace those detailed in Basic.

Lucky (Advantage, mental):
The characters Luck score increases by 2 and the player receives an additional Luck Point at the start of an adventure (when Luck Score default is 8) OR The characters Luck score increases by 1 and the player receives an additional Luck Point at the start of an adventure (when the Luck Score default is 9). Cost: ???
Unlucky (Disadvantage, mental):
The characters Luck score decreases by 1 and the player receives one less Luck Point at the start of an adventure (when Luck Score default is 8) OR The characters Luck score decreases by 2 and the player receives one less Luck Point at the start of an adventure (when the Luck Score default is 9). Cost: ???

As I’m really new at GURPS and as I’m not 100% happy with the mechanics I would like to hear some opinions about this :-)
Do you like the idea? Do you propose any changes? What would you suggest for the point costs for the two traits?

*Theoretically most creatures would have a Luck score, but it only matters for the Player Characters.

[sir_pudding]

This seems like Destiny and/or Serendipity (using the point pool options from Impulse Buys) with Unreliable. IMO, I wouldn't bother with the activation roll and just use those traits as is.

[Boomerang]

I would be inclined to make it more similar to how it works in the FF game books. For example a successful use of luck either doubles the damage you inflict on an opponent (before DR is subtracted) or halves the damage you take (again before including DR) when wounded.

Outside of combat the GM specifies a luck check whenever another check is not more appropriate. For example: does the ogre return to the cave while you are still in there? Or when the player specifically asks for one. Does the guard uniform happen to fit my character perfectly?

Luck should be an attribute. Initial luck should be 10 and be increased up or down at a cost of five points per level. Roll 3d6 instead of 2d6 though (it is gurps after all). Subtract one from current luck every time it is used and current luck restores to its initial level at the start of each adventure. Certain events, blesses or curses may temporarily reduce or increase current luck at the GM's discretion.

[Ashtagon]

I'd be tempted to use the "spent a CP to do/reroll stuff" mechanic seen in one of the gurps books, possibly with modifications.