Thinking About d20 Chases

[Water Bob]

I would like to incorporate more chases in my game. I like the idea of adrenaline fueled romps through thick forest, over fallen logs, across shallow streams and long fields as well as frantic, jerky, desperate flights through the urine-splashed streets of the Maul, over roof tops, through windows, over fences, bashing through crowds, etc.

I've already run two big chases in my campaign--one an endurace-test, prove-you're-a-man type of natural obstacle course for my warrior Cimmerians while the other was a desperate chase to catch the bad guys set among the limbs of these huge trees called Thicket Trees. In both cases, I just made up a quick chase system (each race used a different system) using the mechanics provided in the game (attribute checks, mainly, and checks to avoid obstacles). What I did served the purpose for the scenario, but I wasn't 100% happy with either set of mechanics I developed for those game sessions. I want something that easy to pull out at a moments notice and incorporate in a game.

I've looked at Hot Pursuit (and Hot Pursuit on Foot), Pathfinder's Gamemastery Chase mechanics, and the Chase system in d20 Spycraft. I could very well end up using one of those systems, but at the moment, all three seem a bit overly complicated with a bit of a learning curve required.

I've been thinking that the game really does (or should) give us all we need to run chases--I've just got to come up with a standard set of easy-to-use rules.

Well, in thinking about it, here's what I've come up with. I'll spell it out for you, and you tell me what you think. Maybe you can help me come up with a better system.



NOTE: I play a d20 clone in the form of the CONAN RPG, which is a lot like 3.5 D&D but with enough mechanical changes to give the CONAN game its own, distinct flavor apart from the parent game. I am developing these rules for that RPG, but, it being a d20 game, I think these rules would be useable with little or no changes for any d20 based game that you happen to be playing.

These aren't completed, play-tested rules. This is me brainstorming, deciding on whether I should polish what I've got here or incorporate one of the Chase rule systems mentioned above.

 

[Water Bob]

d20 CHASE RULES



PLUG-N-PLAY: The rules (a develoment goal) need to be easy to use, plug-n-play with the Core Rulebook. This means that the Chase rules should welcome and not invalidate Feats like Fleet-Footed and Run.

Chases are really just another form of movement. Rounds during a chase are played out in standard Combat Rounds. Because a character will be moving, he'll use his Move action as normal (which means there are no Full Actions during Chases). And, since most Chases happen at high speed, rarely will a character on foot do more than move during the round (checks to avoid obstacles are generally considered part of the move action). Characters riding horses and the like are restricted, as well, per the normal rules. Passengers are able to act normally.



TACTICAL SCALE: The vast majority of chases will happen on the Tactical scale. Chases that occur on the Local or Overland scales tend to wash and average--thus normal movement rules should be used. Given that the Conan RPG is a Swords & Scorcery game (as opposed to a High Fantasy game like D&D), most chases will feature characters running or riding horses or camels. The rules can be easily adapated to, say, two ships on the ocean, each making a run for the nearest island to be first at the buried treasure.



CONSTITUTION: Running is about physical fitness and endurance. The d20 attribute that embodies that aspect is CON, therefore CON is the base attribute used in the Chase Rules. But, the system is flexible in that the GM may change the base attribute when needed. If the challenge of a Chase is long distance--a marathon that tests a character's endurace--then CON is perfect. But, if a Chase leads the characters over the tops of rocks to cross a river, then, at least for that obstacle, DEX may be a better choice.

GMs should also use skills such as Balance, Jump, Swim, Ride, and Climb when appropriate. Other skills could come into play during a chase as well.

 

[Water Bob]

MOVEMENT DIFFICULTY

Unlike a normal combat round, during a chase, a character must roll against a DC to make a successful Move action. The DC is based on terrain, speed, and any other factors the GM deems pertinent.

As a rule of thumb: Flat, unobstructed, easy to transverse terrain has a DC 5. This makes it very unlikely but possible that a fumble or crash will happen. Factors that make transversing the terrain more difficult (faster speed or terrain that is more difficult to navigate) push the DC higher.

The GM can raise the Chase DC in increments according to the standard d20 DC chart (DC 5, DC 10, DC 15, etc), or he can raise it any amount he thinks correct for the situation.

The GM can also declare what happens when a DC is failed. In most situations, a failed Chase check just means that the character did not move faster than his base move and may have moved slower than normal. On particularly hazardous terrain, the GM can insert chances to fall or other appropriate penalties.



Chosing a Chase Difficulty...

This is the realm of the GM and best described with example situations. Let's say the terrain is a flat, easy to navigate trail with no obstacles. That's DC 5 terrain if the character Walks. The player would throw d20 + CON modifier for a total of 5+.

Remember the three movement modes in a d20 game: Walk, Hustle, Run; or Move, Double Move, Quadruple Move.

If the character crawls, the GM may lower the Chase difficulty to DC 0. If the character Hustles (double move), then the GM raises the Chase difficulty by one level to DC 10. If the character runs, then raise the difficulty two levels to DC 15.

Flat Terrain
------------
DC 0 - Crawl
DC 5 - Walk
DC 10 - Hustle
DC 15 - Run

After speed is considered, the GM should decide whether the terrain should increase or decrease the difficulty more than the DC appropriate for speed. For example, let's say a flat corridor made of cut-stone includes puddles of oil splashed on the floor by an enemy. The GM may decide to increase the Chase Difficulty because of the terrain.

OTOH, let's say that the terrain is not flat but a gentle slope. A slope is harder to transverse than flat terrain, but the GM decides that the DC should not be elevated from the difficulty assigned by the speed decision. This is all in the realm of the GM's decison.

 

[Water Bob]

CHASE MOVEMENT

Chases are handled just like any other combat round except that a check is made for movement.

CRAWL - A character improves his distance by 5 feet for every 20 points he rolls over the Chase DC. The character shortens his standard distance by 5 feet for every 20 points he rolls under the Chase DC.

WALK - A character improves his distance by 5 feet for every 15 points he rolls over the Chase DC. The character shortens his standard distance by 5 feet for every 20 points he rolls under the Chase DC.

HUSTLE - A character improves his distance by 5 feet for every 10 points he rolls over the Chase DC. The character shortens his standard distance by 5 feet for every 20 points he rolls under the Chase DC.

RUN - A character improves his distance by 5 feet for every 5 points he rolls over the Chase DC. The character shortens his standard distance by 5 feet for every 20 points he rolls under the Chase DC.

Basically, if the character's Chase check results in 20+, then he moves father than allowed him by his base Speed. And, the faster a character moves, the more likely it is that he will move slower than his base Speed.



Consider this....

Flat Terrain
------------
DC 0 - CRAWL
DC 5 - WALK
DC 10 - HUSTLE
DC 15 - RUN

CRAWL - If the Chase throw results in a number that is 20+ (20 over DC 0), then the distance crawled is increased by 5 feet. When crawling, it is virtually impossible to crawl slower than a character's base crawl speed on flat terrain.

WALK - If the Chase throw results in a number that is 20+ (15 over DC 5), then the distance walked is increased by 5 feet. It is most likely impossible to Walk less than a character's base Speed unless the character is hindered by large modifiers. A character with a low CON (possibly poisoned?) and movement penalties could conceiveably have a -11 on the throw, which is what it would take to lower the character's throw to 15 points below the Chase DC 5 target number.

HUSTLE - A Hustle is basically a jog, and most chases will occur at either Hustle or Run speeds. If the terrain can be described as Difficult, then, by the d20 rules, the character's max speed is his Hustle rate. On flat terrain, the character can move 5 feet faster than his base Hustle rate if he throws a 20+ on his DC 10 Chase check. If he manages a 30+ on the throw, the character can move 10 feet faster than his base. The character is safe, moving at his base speed, on a Chase check of 1-19, but negative modifiers can bring the throw to 0 or less--which would indicate that the character's base speed needs to be reduced by 5 feet for that round.

RUN - If not in Difficult terrain, then a character involved in a foot chase can run at 4x Speed (3x Speed if encumbered by Heavy Armor). The DC for running on flat terrain is DC 15, and every 5 points above or below that number indicates a change to the character's base Speed. A Chase check of 20-24 means the character's Speed is increased by 5 feet. A result of 25-29 increases Speed by 10 feet. A result of 30-34 increases speed by 15 feet, and so on. Likewise, the character moves at normal speed on a roll of 11-19. A roll of 6-10 means the character moves 5 feet less than normal. A roll of 1-5 means that the character moves 10 feet less than normal that round. And a roll of -4 to 0 means the character moves 15 feet less than normal (and so on). The GM should provide the color for shorter movement rates, describing how the character slipped, slid, fell and got up, or whatever, during the combat round.

 

[Water Bob]

NOTES

During a normal combat round, in a non-chase situation, think of the character doing something akin to Taking 10 on his movement check, arriving at a total that will result in a Base Move as described above. For example, consider a character with CON 16 making a DC 15 Chase check while Running. Taking 10 nets this character a total of 13, which puts him in the safe zone of 11-14, meaning the character moved at his base move.

Now, this isn't a perfect use of the rules. The Take 10 rule cannot be used in combat situations, and a character with a CON modifier of +5 or more would indicate faster movement than the character's base Run Speed. But, the general idea can be used if a player asks why the Chase check (movement check) isn't used in all situations. The Take 10 does work for the other movement classes (Walk and Hustle) as well as when crawling. The Chase check should only be used when chases happen in a game. And, when those chases do happen, they will most likely happen with the character moving as fast as he can at either a Hustle or Run movement class.

There are some situations where these Chase rules can be used at other movement classes. In a crowd, for example, where a character is trying to keep a low profile and not be seen but is still attempting to make it to a spot before his enemy, the character may be walking as fast as he can while at the same time trying not to attract attention. This situation would call for a DC 5 Chase check with the character walking, and a roll total of 20+ will gain the character +5 feet to his Walk movement during the round. This is the realm of the GM--to make the rules custom fit a situation--and, if it were me GMing such an encounter, I'd make the particpant use the Hide skill for the Chase checks.



When a Chase breaks out in a game, consider these few comments....

1. Run the Chase just like normal combat. All standard rules are observed.

2. When in a chase, the character will roll for success on their movement, using the guidlines expressed above.

3. The check to avoid an obstacle or perform a maneuver during the chase is typically not considered a separate action but rather part of the Move action taken during the round. At the same time, during a foot chase, a character can do little else, per the rules, if moving at a Hustle or faster.

4. When picking a DC for the Chase throw, use the chart above and consider the character's Speed and movement class first. Once that DC is established, decide whether terrain conditions warrant the raising or lowering of the Chase DC.

5. Remember that on Difficult terrain, per standard d20 rules, a character's max move is a Hustle.

6. Chases can be played out on a combat grid, but maps are not necessary. All a GM really needs to track is the distance between the pursuer and the person being chased. This is easily notated by the starting distance between the two, the speed of each Chase participant, and the distance gains or losses each makes during the round.

7. Failing a Chase check typically results in no penalty to the character unless the check total indicates the character's base Speed has been reduced. It is up to the GM to decide when it is hazardous to fail a Chase check. For example, in a Chase around a narrow mountain ledge, the GM may decide that any natural roll of 1 on the Chase check indicates the character might fall off the side unless the character makes a Reflex saving throw. Or, when running across a field that features many stones, boulders, and holes, failing the Chase DC by 5+ might indicate the character has fallen and strained his ankle--the result being a penalty of half movement. This type of ruling may encourage Chase participants to move more slowly and carefully (reducing the Chase DC) over such terrain--and rewarding those that throw caution to the wind and succeed on the Chase checks across the field.

 

[Water Bob]

CHASE EXAMPLE

Two PC's, Silaigne and Caelis, are just outside of their clanholme when they come across an upturned wagon. The wagon carried an old woman and several children. Most, now, are lying around the cart. One of the two mules lies motionless, and the second lies near it, still alive but downed with a javeling sticking out of its neck. Among the wreckage are two warriors from a neighboring clan with which the PC's clan has a blood feud.

This is an atrocity! The characters are incensed!

The GM says, "As you approach, the two Grath warriors see you. It looks as if they are walking among the dead, stripping the bodies of what little they have. At first sight, the two Grath beging to run. The trail and upturned wagon are on a hill. The direction the Grath run has a gentle slope downward, towards the bottom of the hill."

Silaigne: "I'm moving as fast as I can towards the closest one. My spear is already in one hand. As I move, I'll pull my dirk from my belt with my other hand."

GM: "The chase is on! Starting distance between you and the closest Grath is 145 feet. Roll initiative!" Grath-1 wins nish, followed by Silaigne, followed by Grath-2, with Caelis picking up the end of the combat round.



ROUND 1

Gerald's Turn...

GM: "On flat terrain, it's a DC 0 to crawl, raised to DC 15 for a run. Normally CON is used as the base chase attribute, but in this situation, the terrain has a slight slope downwards. There's pockets of loose skree and small obstacles like rocks, an uneven terrain surface, and downed tree trunks to avoid. The terrain is considered Difficult, thus a Hustle is the maximum movement class. Though a normal Hustle on flat terrain indicates a DC 10 Chase throw, I think this terrain warrants the DC 15, and the Balance skill can be used in place of your CON modifier--whichever is higher.

"You see the closest Grath warrior run as fast as he can down the slope. He's at a Hustle. His movement base is Speed 60. He's a white skinned Cimmerian warrior with long, dark hair and a beard. Both hair and beard include braids. He wears leather sandals, a kilt made of some type of reptile skin, and a cotton, billowy shirt. Across his chest is a wide strap with daggers and sheaths secured there. On his back is a large, deep quiver--a javeling quiver. You can see two javelins protruding from its top. In his right hand, he carries a third javelin."

The GM makes the Grath's Chase check: Grath-1, "Gerald", is Balance +1. d20 = 17 + 1 = 18 vs DC 15.

"The Grath moves horizontally from you, down the slope, 60 feet. The diagonal from you to him is now 175 feet after you avoid the downed mules."



Silaigne's Turn...

Silaigne: "Doing as I said, running straight for him."

DC 15. Silaigne is Balance +2. Base Hustle Speed is 60'. d20 = 1 + 2 = 3. This is 12 points less than the DC which means (using the Run conditions in the above rules because, in effect, the characters are moving as fast as they can--it's the terrain that shortens the distance covered, not their effort) that Siliagne loses 10 feet from his Base move this round.

GM: "Your reaction is slow, and you slip on the skree, almost falling, as you run around the mules. You moved 60 - 10 = 50 feet. Now, the distance between you and the Grath is 125 feet."



The Turn For The Other Two...

The second Grath warrior is up next, but instead of running after the first Grath, the GM has him move to engage Caelis in melee combat. To keep the example simple, we'll assume that their battle takes the rest of the Chase encounter to complete. When playing this out, I would skip back and forth beween the Silaigne-Gerald chase and the Grath 2-Caelis fight so that neither gets ahead of the other. In a real game, Caelis could certainly kill the Grath quickly and then move to affect the chase. But, in deference to simplicity, assume Caelis continues to battle the second Grath warrior while the chase proceeds.

 

[Water Bob]

ROUND 2

Gerald's Turn...

GM: The Grath continues to run for the bottom of the hill. He'll make it this round if he completes 60 more feet. The distance between you and him at the start of the round is 125 feet.

The Grath makes his Chase check. d20 = 15 + 1 = 16. vs. DC 15. "He makes it to the bottom of the slope. Range before your move is 185 feet."



Silaigne's Turn...

Silaigne: "I yell, at the top of my lungs, 'Stop, you slayer of children! Stop, or by Crom I'll make you wish you had!'"

GM: "There's no response from the Grath, though he does look over his shoulder at you."

Silaigne: "Can I see his eyes?"

GM: "Not really. But the expression on this face is neutral. He doesn't seem frightened."

Siaigne's Chase check: d20 = 17 + 1 = 18. vs. DC 15.

GM: "You get your full, standard movement this time. 60 feet. At the end of the round, distance between you and the Grath is 125 feet."

 

[Water Bob]

ROUND 3

Gerald's Turn...

GM: "As the Grath runs off the bottom of the hill, the slope disappears, but the terrain stays in the same condition. Because the slope is gone, I'm lowering the DC by 2 points. Your Chase checks are at a DC 13 now.

"A few feet from the base of the hill, knee high grass begins to grow. Some obstacles may be hidden from long distance sight. Each round, I'm making a 1-in-10 chance that there is an obstacle that is discovered in the path at the last second. These obstacles are mainly rocks, holes, and downed pine trunks.

"If Silaigne follows directly behind the Grath, then he will have to overcome the same obstacle but will be aware of it and have a chance to go around it. If Silaigne follows the Grath on a separate path, then you'll have the same chance at obstacles has he does, which is 1-in-10.

As the round commences, the GM secretly rolls for Gerald's obstacle. There's nothing in his path this time. Gerald makes his run: d20 = 15 + 1 = 16 vs. DC 13. Gerald moves base Speed again.



Silaigne's turn...

Silaigne: "I'm following directly behind the Grath."

Silaigne's Chase check: d20 = 13 + 2 = 15. Pace is matched. Distance between them is still 125 feet.







ROUND 4

Gerald's Turn...

There is an obstacle this time. Near the end of the round, Gerald comes runs into a patch of grass that hides a tree trunk. He sees it, last minute, and the GM will give him a DC 10 Jump check to clear it. Or, the NPC can end the round after he's made it 40 feet. Or, the NPC can roll his Chase check with a -5 penalty to account for the time it takes to run around the log.

Any failure on the Jump check means the character slips when jumping over the log and ends the round prone.

Gerald needs to make two checks this round. First, he attempts the standard Chase check at a DC 13 (since Gerald is going to attempt to Jump the log). Second, the Jump check is considered part of movement--not a separate action. So, Gerald will have to make a DC 10 Jump check or fall flat and prone after moving 40 feet.

Chase check: d20 = 17 + 1 = 18 vs DC 13. This is 5 points over the DC, so if Gerald makes his Jump over the log, he'll move 65 feet this round.

Jump check: (Gerald's Jump +7) d20 = 17 + 7 = 24 vs DC 10. Gerald flies over the log, no problem. Range between Gerald and Silaigne increases by 5 feet.



Silaigne's Turn...

GM: "Ahead of you, you see the Grath jump over something. He easily makes the jump. It's almost gracefull. You can't see what it is due to the grass. Do you want to attempt to avoid whatever it is he jumped? Do you want to slow down? Do you want to stop? Do you want to plow straight on and be aware that you might be jumping something? What do you want to do?"

Silaigne: "Morrigan's Black Teat! I'm going after that beast!"

Chase check: d20 = 13 + 2 = 15 vs DC 13.

GM: "Through the grass in front of you, you see an old downed log. This is what the Grath jumped over. It's a DC 10 Jump check (the Player did not know the specifics of the obstacle before he saw it).

Jump check: d20 = 11 + 9 = 20. Silaigne easily hurls over the log, too.

GM: "At the end of this round, the Grath made 5 feet on you. Distance between you is 130 feet."

 

[Water Bob]

And, the Chase goes on. I like long chases. Like watching a baseball game, something exciting can happen at any moment. There's suspense.

130 feet is a long throwing distance. Silaigne probaby wants to close ground enough to get off a decent throw with his spear. With the longer range of the javelin, Gerald could maybe improve his position by stopping and throwing his javelin at Silaigne. Gerald might even want to slow his speed a bit, allowing Silaigne to close the gap so that Gerald's throwing distance isn't as challenging.

What would really be interesting, though, if one of them misses an obstacle and falls. That's what Silaigne needs. If he could get close to the Grath, Silaigne could leap and attempt to tackle Gerald. That would be a Grapple attempt, and this action would lead to the two duking it out in a fist fight out on the Cimmerian plains.

A lot could happen.





Well, that's my idea of using the game's rules to govern chases. What do you think?

 

[Water Bob]

QUICK NOTES FOR THESE CHASE RULES

Flat Terrain           +/-  5' Speed
----------------     ------------------
DC 0     CRAWL              20       
DC 5     WALK               15
DC 10    HUSTLE             10
DC 15    RUN                 5

Figure Speed DC first, then decide if change for terrain is needed.