GURPS Combat Choices: Deceptive Attack and Telegraphic Attack

Update: Martin Leuschen pointed out an error in the table, since fixed. My thanks to Martin for keeping my honest.

Patric Halter over at Renovating the Temple beat me to it with this post, but here is my take on Deceptive Attack and Telegraphic Attack.

In GURPS combat, Deceptive Attack is a combat option that lets you penalize your opponent's defense by -1 for every -2 you take to your attack roll. The only limits are your GM's indulgence, and a minimum final skill level of 10.

Telegraphic Attack, on the other hand, is a combat option that goes in the other direction: you can add +4 to your attack skill, but your opponent's defense increases by 2. Unlike DA, you don't get to pick how much Telegraphic Attack you want to use: it's +4/+2 or nothing. Also, TA doesn't affect your chances of scoring a critical hit. To determine if you got a critical, you use the skill you had before adding the TA bonus.

So, when do you want to use Telegraphic Attack? When do you want to use Deceptive Attack, and how much? Here's a handy table I made.

	Defense
Attack	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20
3	TA	TA	TA	TA	TA	TA	TA	TA	TA	TA	Flee	Flee	Flee	Flee	Flee	Flee	Flee	Flee
4	TA	TA	TA	TA	TA	TA	TA	TA	TA	TA	TA	Flee	Flee	Flee	Flee	Flee	Flee	Flee
5	TA	TA	TA	TA	TA	TA	TA	TA	TA	TA	TA	Flee	Flee	Flee	Flee	Flee	Flee	Flee
6	TA	TA	TA	TA	TA	TA	TA	TA	TA	TA	TA	Flee	Flee	Flee	Flee	Flee	Flee	Flee
7	TA	TA	TA	TA	TA	TA	TA	TA	TA	TA	Hold	Hold	Flee	Flee	Flee	Flee	Flee	Flee
8	TA	TA	TA	TA	TA	TA	TA	TA	TA	TA	Hold	Hold	Hold	Flee	Flee	Flee	Flee	Flee
9	TA	TA	TA	TA	TA	TA	TA	TA	Hold	Hold	Hold	Hold	Hold	Flee	Flee	Flee	Flee	Flee
10	TA	TA	TA	TA	TA	TA	TA	Hold	Hold	Hold	Hold	Hold	Hold	Flee	Flee	Flee	Flee	Flee
11	TA	TA	TA	TA	TA	TA	Hold	Hold	Hold	Hold	Hold	Hold	Hold	Flee	Flee	Flee	Flee	Flee
12	TA	TA	TA	TA	Hold	Hold	Hold	Hold	Hold	Hold	DA 1	DA 1	DA 1	DA 1	Flee	Flee	Flee	Flee
13	TA	TA	Hold	Hold	Hold	Hold	Hold	Hold	Hold	DA 1	DA 1	DA 1	DA 1	DA 1	Flee	Flee	Flee	Flee
14	Hold	Hold	Hold	Hold	Hold	Hold	Hold	DA 1	DA 1	DA 1	DA 1	DA 2	DA 2	DA 2	DA 2	Flee	Flee	Flee
15	Hold	Hold	Hold	Hold	Hold	Hold	Hold	DA 1	DA 1	DA 1	DA 2	DA 2	DA 2	TA	TA	TA	Hold	Hold
16	Hold	Hold	Hold	Hold	Hold	Hold	Hold	Hold	DA 2	DA 2	DA 2	DA 2	Hold	Hold	Hold	Hold	Hold	Hold
17	Hold	Hold	Hold	Hold	Hold	DA 1	DA 1	DA 1	DA 2	DA 2	DA 3	DA 3	Hold	Hold	Hold	Hold	Hold	Hold
18	Hold	Hold	DA 1	DA 1	DA 1	DA 1	DA 1	DA 1	DA 1	DA 3	DA 3	DA 3	DA 3	DA 1	DA 1	Hold	Hold	Hold
19	Hold	Hold	DA 1	DA 1	DA 1	DA 1	DA 2	DA 2	DA 2	DA 3	DA 3	DA 3	DA 4	DA 1	DA 1	Hold	Hold	Hold
20	Hold	Hold	DA 1	DA 2	DA 2	DA 2	DA 2	DA 2	DA 2	DA 2	DA 4	DA 4	DA 4	DA 4	DA 2	DA 2	Hold	Hold
21	Hold	Hold	DA 1	DA 2	DA 2	DA 2	DA 2	DA 3	DA 3	DA 3	DA 4	DA 4	DA 4	DA 5	DA 2	DA 2	Hold	Hold
22	Hold	Hold	DA 1	DA 2	DA 3	DA 3	DA 3	DA 3	DA 3	DA 3	DA 3	DA 5	DA 5	DA 5	DA 5	DA 3	DA 3	Hold
23	Hold	Hold	DA 1	DA 2	DA 3	DA 3	DA 3	DA 3	DA 4	DA 4	DA 4	DA 5	DA 5	DA 5	DA 6	DA 3	DA 3	Hold
24	Hold	Hold	DA 1	DA 2	DA 3	DA 4	DA 4	DA 4	DA 4	DA 4	DA 4	DA 4	DA 6	DA 6	DA 6	DA 6	DA 4	DA 4
25	Hold	Hold	DA 1	DA 2	DA 3	DA 4	DA 4	DA 4	DA 4	DA 5	DA 5	DA 5	DA 6	DA 6	DA 6	DA 7	DA 4	DA 4
26	Hold	Hold	DA 1	DA 2	DA 3	DA 4	DA 5	DA 5	DA 5	DA 5	DA 5	DA 5	DA 5	DA 7	DA 7	DA 7	DA 7	DA 5
27	Hold	Hold	DA 1	DA 2	DA 3	DA 4	DA 5	DA 5	DA 5	DA 5	DA 6	DA 6	DA 6	DA 7	DA 7	DA 7	DA 8	DA 5
28	Hold	Hold	DA 1	DA 2	DA 3	DA 4	DA 5	DA 6	DA 6	DA 6	DA 6	DA 6	DA 6	DA 6	DA 8	DA 8	DA 8	DA 8
29	Hold	Hold	DA 1	DA 2	DA 3	DA 4	DA 5	DA 6	DA 6	DA 6	DA 6	DA 7	DA 7	DA 7	DA 8	DA 8	DA 8	DA 9
30	Hold	Hold	DA 1	DA 2	DA 3	DA 4	DA 5	DA 6	DA 7	DA 7	DA 7	DA 7	DA 7	DA 7	DA 7	DA 9	DA 9	DA 9

Caveat: this table only considers Deceptive Attack and Telegraphic Attack. If you also considered Rapid Strike, Dual Weapon Attack, hit locations, or other combat options, things would change a lot. But that will have to wait for later.

The attacker's skill runs along the side, and the defense runs across the top. The entry for a given skill and defense shows your best choice. "Hold" means that you can't improve your chances with either a Deceptive Attack or a Telegraphic Attack; you're already at the best level. "Flee" means that no matter what you do, your attack is going to be worth less than zero. Yes, I mean that on your own turn, you are more likely to get hurt than to hurt your opponent. Might as well run away.

You probably don't want to waste time looking things up on this table all the time, so let me try to reduce this information to a few rules of thumb.

1. Don't use Deceptive Attack if your opponent's defense is already at 3 or 4. 
2. Don't use Deceptive Attack unless you can get your opponent's defense below 13.
3. If the sum of your skill and your opponent's defense is above 24, try to bring it down to the range of 22 to 24. Each level of DA will reduce the sum by 3.
4. If the sum of your skill and your opponent's defense is 19 or below, use Telegraphic Attack.
5. But don't use Telegraphic Attack if your skill is above 13.
6. If your opponent's defense beats your skill by 8 or more, don't even try making an attack this turn. 

These rules don't get you optimal results in all cases, but they cover most of the chart pretty well.

For those of you interested in all the math behind the scenes, for now I'll just say that in this table, I considered the value of a normal hit to be 1, and discounted it by the probability that it gets past the defense. Then I valued a critical hit on the attack at 1.3, a critical failure on attack at -1.5, and a critical failure on defense as worth an extra 0.1. A critical success on defense imposes a critical failure on the attacker, and so is also worth -1.5.

These numbers are somewhat arbitrary, and anyone could reasonably question them, but after fiddling around with various values, I find that they don't alter the results very much.

A more detailed explanation of the number-crunching behind the chart will have to wait for another day.