Combat Math: The Cluster Table

Catalyst Games Labs recently commented that the 12th printing of the standard core BattleTech rulebook, Total Warfare, would be the last. Looking ahead, CGL are planning to reformat the rules, potentially making some optional rules part of the core mechanics and even… changing the cluster hit mechanic….

Since the earliest printing of the BattleTech core rules, the cluster table has been a mainstay. Intended to represent the degradation in the technology of the guidance systems of missile systems, “Cluster Weapons” would hit with a random number of munitions after you had rolled to hit, and independently of the to-hit role.

Originally in the Introductory level technology (3025) cluster tables were only used for LRMs and SRMs. In these early versions, the cluster table only included 2/4/5/6/10/15 and 20 columns.

After the clan invasion of 3050 (and in the Technical Readout 2750, new/LosTech systems would modify the cluster table e.g. Artemus IV and NARC beacons. Cluster rolls were also added for the new Ultra AutoCannon/5, and the AutoCannon/LB-10X.

As the timeline progressed, new Cluster weapons were added, including: MRM’s, MML’s, clan ATM’s, UAC 2/5/10/20, LB-X 2/5/10/20, HAGs, Silver Bullet Gauss Rifles, RAC 2/5 and probably more that I’ve forgotten to include… The cluster table was also increased to cover every number from 2 to 40!

In addition to these, Mech and Vehicle scale weapons, Conventional Infantry and Battle Armor also made extensive use of the Cluster mechanic to determine the number of troopers that hit (both with Anti-Personnel and BA Mech Scale weapons).

In summary, in the Standard game (Total Warfare) and beyond, the cluster table mechanic is an integral component to the game.

So what are the issues with this, and why is there a growing movement (including by CGL) to look at moving away from this mechanic?

Yet another table?

At almost every BattleTech table you’ll find players brandishing the hard cardstock quick reference table. Generally, this isn’t because they need to look up MP costs or modifiers to hit, but because they are constantly needing to look up cluster hits.  In many cases, the IntroTech card stock table is not enough, and you’ll need to crack open Total Warfare of the BattleTech manual for the full table. Some people (like me) make use or record sheets from MegaMek or Flechs that print the cluster tables on the sheets – I particularly like MegaMek as it prints the cluster columns only for the weapons you have. Even experienced players, like myself, don’t have the whole table committed to memory.

So does the game need this delay of looking up yet another table>

Time is the fire in which we burn

We all know that BattleTech can be a long game.  A lance vs lance game easily takes 2-3 hours, while a company/star level game can be a whole day 7-8 game!

I once went to an event at a FLGS, where we had a Star-on-Star game, and I was that guy who bought the Bane (Kraken) 3. For the uninitiated amongst you, the Bane 3 has 8 x Clan LRM 15’s and ammo for days. In one attack, I was rolling 8 to hit rolls, followed by 8 cluster table rolls, followed by up to a maximum of 24 separate cluster hits. And although I make use of multiple sets of coloured dice, by the end of the attack, my opponent was looking a little shell-shocked, by both its damage output and the number of rolls.

If you want to really see a grown man cry in anguish, then roll out an SRM carrier with 10 SRM6’s and add to that the Inferno or Tandem Charge Warheads mechanic…. One attack could take 10-15 minutes to resolve.

Is there a way in which the number of dice rolls can be reduced? Can some dice rolls even be eliminated?

How does the cluster system currently work?

For those interested in the Math (I apologise to my fellow UK readers for omitting the s in Maths), then the mechanic is quite simple. You roll the classic BattleTech 2d6, which gives a bell-shaped probability curve (no – please don’t mention using 1D12’s….) and apply it to the table. But what is the math behind the cluster table? The table below shows the % number of hits for each column.

Roll	%	Inc %	2	%	4	%	5	%	6	%	10	%	15	%	20	%
2	2.8	100	1	50	1	25	1	20	2	33.3	3	30	5	33.3	6	30
3	5.6	97.3	1	50	2	50	2	40	2	33.3	3	30	5	33.3	6	30
4	8.3	91.7	1	50	2	50	2	40	3	50	4	40	6	40	9	45
5	11.1	83.4	1	50	2	50	3	60	3	50	6	60	9	60	12	60
6	13.9	72.3	1	50	3	75	3	60	4	66.7	6	60	9	60	12	60
7	16.7	58.4	1	50	3	75	3	60	4	66.7	6	60	9	60	12	60
8	13.9	41.7	2	100	3	75	3	60	4	66.7	6	60	9	60	12	60
9	11.1	27.8	2	100	3	75	4	80	5	83.3	8	80	12	80	16	80
10	8.3	16.7	2	100	3	75	4	80	5	83.3	8	80	12	80	16	80
11	5.6	8.4	2	100	4	100	5	100	6	100	10	100	15	100	20	100
12	2.8	2.8	2	100	4	100	5	100	6	100	10	100	15	100	20	100

Advanced Cluster Rules

Several Advanced rules exist to enhance/complicate the cluster rules further. These can be found in Tactical Operations: Advanced Rules

• Glancing Blow pg. 78 TO: AR
• Direct Blow pg. 79 TO: AR
• Cluster Hit Penalties pg. 82 TO: AR
• Extreme Ranges pg. 83 TO: AR

HOUSE RULES

From this point on, all the rules presented here are house rules – not found in any book. Many of these are commonly played by groups and may inform CGL on any changes that may be made to the future of the cluster rules mechanic.

Fairer Cluster Table

Although not a rule that will speed up game play – the below fairer cluster table works on a wider range of percentages.

Advantages/Disadvantages –  This system does allow for a greater range of outcomes and a potentially fairer spread, but the table is harder to memorise as it has more bands.

Roll	%	Inc %	2	%	4	%	5	%	6	%	10	%	15	%	20	%
2	2.8	100	1	10	1	10	1	10	1	10	1	10	2	10	2	10
3	5.6	97.3	1	20	1	20	1	20	2	20	2	20	3	20	4	20
4	8.3	91.7	1	30	2	30	2	30	2	30	3	30	5	30	6	30
5	11.1	83.4	1	40	2	40	2	40	3	40	4	40	6	40	8	40
6	13.9	72.3	1	50	2	50	3	50	3	50	5	50	8	50	10	50
7	16.7	58.4	2	60	3	60	3	60	4	60	6	60	9	60	12	60
8	13.9	41.7	2	70	3	70	4	70	5	70	7	70	11	70	14	70
9	11.1	27.8	2	80	4	80	4	80	5	80	8	80	12	80	16	80
10	8.3	16.7	2	90	4	90	5	90	6	90	9	90	14	90	18	90
11	5.6	8.4	2	100	4	100	5	100	6	100	10	100	15	100	20	100
12	2.8	2.8	2	100	4	100	5	100	6	100	10	100	15	100	20	100

The Pilot and Cluster Dice

In this system, for each attack roll the player rolls 1 Pilot dice, one Weapon dice and if it’s a cluster attack, then one “cluster dice”. The hit roll in the Pilot plus Weapon dice, then for the Cluster Table, you use the Pilot dice plus Cluster Dice.

Advantages/Disadvantages—Some players feel this is faster and also like to combine it with the rule where a player only rolls one Pilot dice per attack and one weapon dice for each weapon. However, it does require separate dice colours, and a good/bad Pilot dice roll can cause all attacks to be good/bad, making it a more “swingy” system.

 MoS/MoF Cluster Table

In this system, you only roll an attack roll, but to work out the cluster hits you use the margin of success/margin of failure of the attack roll. Any modifiers to the Cluster Roll are added to the to hit dice roll.

Advantages/Disadvantages—This uses a whole different mechanic, which changes the cluster mechanic a bit, but it involves one fewer die roll.

MoS	2	%	4	%	5	%	6	%	10	%	15	%	20	%
-4	0	10	0	10	1	10	1	10	1	10	2	10	2	10
-3	0	20	1	20	1	20	1	20	2	20	3	20	4	20
-2	1	30	1	30	2	30	2	30	3	30	5	30	6	30
-1	1	40	2	40	2	40	2	40	4	40	6	40	8	40
0	1	50	2	50	3	50	3	50	5	50	8	50	10	50
1	1	60	2	60	3	60	4	60	6	60	9	60	12	60
2	1	70	3	70	4	70	4	70	7	70	11	70	14	70
3	2	80	3	80	4	80	5	80	8	80	12	80	16	80
4	2	90	4	90	5	90	5	90	9	90	14	90	18	90
5	2	100	4	100	5	100	6	100	10	100	15	100	20	100

No Cluster Roll

A rather extreme house rule, but this rule considers all cluster rolls to be 8 by default (which is how AeroSpace cluster rules also work). Modifiers do change this number.

Advantages/Disadvantages – While effective at time saving, this might seem to take out some of the character of cluster weapons.

Weapon Grouping Cluster roles

An extension to the cluster rules – in this rule, all weapons that are in a single location are fire-linked. You only roll one to hit roll, and then roll on the cluster table for the number of weapons that hit. E.g. A Hunchback has 6 Medium Lasers in its left torso, so you make one hit roll and if successful you then roll on the cluster table to see the number that hit.

Advantages/Disadvantages – This can lead to a boom or bust situation with potentially all weapons missing more often, but does work in a similar way to RACs

In Summary

You might think from reading this article that I’d be in favour of changing the cluster rules, but in reality, I feel they are a fundamental part of the character of the game, making Cluster weapons feel much different to Direct Ballistic or Energy weapons.

If there is one rule I’d like to trial more, it would be the MoS/MoF Cluster Table.

Let us hope that CGL consider carefully any changes to the cluster system before they publish the successor to Total Warfare.

What do you like or dislike about the cluster rules? What house rules do you use, if any? How do you want CGL to change the cluster mechanic, if at all!

Leave your comments here, on FB or Discord! Maybe CGL will read them.