Imperium, 3rd Millennium
Old Imperium style combat rules by Henry J Cobb
$Id: oldcombat.txt,v 1.3 2005/04/10 21:56:06 hcobb Exp $

I feel that the quick combat rules at the Avalanche Press site discard too
much of the flavor of the game without actually balancing anything so
here's my attempt to make the space battles play like the Old Imperium
game.

First put away the tactical space combat and planet boards as these will
not be used.

Each round of space combat goes through the following steps until at most one
side's ships remain in the battle.

1. Roll for Initiative
2. Determine Range
3. Allocate ships
4. Conduct beam combat
5. Conduct torpedo combat

Roll for Initiative.

The player who activated a system to move ships to the combat automatically
has the initiative on the first round of combat.

On the second and later rounds during any combat both players roll one die
and add the tactical speed of the slowest ship in their forces in this
battle.  (Fighters have a speed of six, light ships have a speed of three
or two if damaged, capital ships have a speed of two or one if damaged and
monitors and non-warships have a speed of one)

The player with the least number of units in the battle adds one to his
initiative roll and the player who had initiative during the last round
adds one to his roll.

Also only on the second round of combat (the first round when initiative is
rolled for) each player subtracts one from his initiative roll for each
fleet marker past the first that he has in this battle.

If the initiative roll is a tie then the player who didn't have the
initiative last round gains it, but is not allowed to change the range this
round otherwise the player with the highest adjusted roll gains the
initiative.

Determine Range.

Combat occurs at two ranges, long and short.

On the first round of a battle the range is automatically long.

On all other rounds the player with the initiative (if the adjusted
initiative roll wasn't a tie) may increase the range one step from long to
disengage or from short to long or may decrease the range from long to
short or may leave the range unchanged from the previous round.

If the player with the initiative moves to disengage then he may load
fighters onto carriers (and Terran Superdreadnoughts) up to their capacity
and land fighters on friendly planets in the system and then all of his
jump capable ships must retreat from the system.

Allocate ships.

If ships from both sides remain in the battle then the player who doesn't
have the initiative selects one of his ships in the battle and places it on
a clear area for the battle.

The player with the initiative then selects of his ships in the battle and
matches it against that ship.

The players alternate matching ships in this matter until one player runs
out of ships in the battle.  At this point if the other player still has
ships that have not been paired he may place these additional ships against
previously matched ships or leave them in reserve and out of the battle for
the remainder of this round.

Conduct beam combat.

Beam combat only occurs if the range is short and is skipped if the range
is long.

For each of the matched groups of ships if one ship with beam factors is
matched against multiple ships then it indicates which enemy ship it is
firing beams against.  Capital ships may split their beam factors between
two of the ships they are matched against if they are matched against more
than one ship.

Then each ship fires its beam factors against one of the ships it is
matched against (or up to two for capital ships) and each ship's fire is
rolled separately with beam factors hitting on a roll of 5 or 6.  If the
number of hits is greater than or equal to the defending ship's screen
factor then the target is damaged or destroyed if hits equal to three times
the target's screen factors were rolled or if the target was already
damaged or it doesn't have a damaged side.

If another ship matched against the target has already damaged it then
further fire against this target is conducted against the damaged screen
factor.  Each player chooses the order he will roll attacks against a
target that he has multiple ships matched against.

Each ship fires with the full beam factor it had at the start of this
round, even if it was damaged or destroyed by the other side's beam fire
during this step.

Conduct torpedo combat.

Once the damage results for beam combat have been resolved then resolve
torpedo combat in the same way except that torpedo fire is allowed at both
short and long ranges, torpedo factors hit on a roll of 5 or 6 and the
target's full countermeasures rating is used against each attacking ship
and counters a torpedo hit on a roll of 5 or 6.

Example: Two terran DDs vs a single Imperial CR at close range.  The CR
selects one DD to fire against.  The first DD rolls a 1 and a 6 for one hit
and no damage.  The second DD rolls a 5 and a 6 and damages the CR.  The CR
then fires at one DD and rolls 2,5,5 and 6 for three hits which destroys
the DD.  Note that if they DDs had rolled their attacks in the opposite
order the CR would have been damaged by the first DD and destroyed by the
second.

Then torpedo combat takes place and the surviving DD rolls a 5 and scores a
torpedo hit while the CR rolls a 4 on countermeasures and is destroyed.
The CR rolls 5, 5 and 6 and hits with all three torpedo factors but the DD
rolls a 3 and a 5 on countermeasures, blocking one hit and so is only
damaged.

Ground combat.

All of the ground combat for a single planet is handled as a single battle
in the same fashion with the following exceptions.

All ground combat is at short range.  Troops attack with beam factors while
planetary defenses and fighters attack with torpedo factors.  Infantry have
a ground combat speed of 1, jump troops have a ground combat speed of 2,
fighters have a ground combat speed of 3 and all other units have a ground
combat speed of zero for the purposes of initiative.

Fleet markers have no impact on ground combat.

Each activation provides for at most three rounds of ground combat on each
planet of the activated system

-HJC