Strategy is the IQ/H skill of planning military operations and predicting the enemy's plans. The defaults are IQ-6, Intelligence Analysis-6 or Tactics-6; both those skills have defaults to Strategy. Specialisation in a broad kind of conflict is required, such as (Land), (Naval) or (Space), and these specialisations default to each other at -4. The specific types of forces are less important: another nation, or even a different TL, would only give -1 or -2, provided you understood their capabilities properly.
With a successful Strategy roll, you can deduce the military plans of an enemy whose leader lacks Strategy. If they have a strategist as leader, you need to win a quick contest of Strategy to deduce their plans. If you fail an uncontested roll, or lose the contest, you get bad information. Of course, knowing the enemy plan is only any use if you can
do something about it. Much of the Mass Combat rules are about contests of Strategy, and the many things that can modify them in a large conflict.
Tactics is the IQ/H skill of organising and winning fights on the scale from small infantry units to personal combat. The defaults are IQ-6 or Strategy-6, and Strategy is the only skill with a default from Tactics.
Tactics has several uses in combat that are often neglected in the games I've played.
- You roll against the best of Perception or Tactics to spot ambushes and surprise attacks, and in cases of Partial Surprise knowing the skill gives your leader at least +1 to initiative rolls.
- If you had any time to prepare for a fight, you can make a Tactics roll to start in an advantageous position (behind cover, higher ground, etc., based on margin of success). If you fail, don't try to use Tactics, or don't know the skill (a default is no use here), you start somewhere determined by the GM.
- If you're in command of a group small enough that you can give all of them orders directly, or through one layer of subordinates, then you can use uncontested Tactics to deploy them correctly for an ambush, post sentries effectively, and possibly get clues as to what the enemy are trying to do. To out-manoeuvre the enemy, gaining some advantage for your command over them, you need to win a contest of Tactics with the enemy leader.
Martial Arts has two optional rules for Tactics that can replace the group rule above. Both involve a quick contest of Tactics between the leaders of each side. In abstract combat, the winner gets re-rolls (like uses of Luck) which he can grant to his allies, if he can describe how tactical factors like formation and cover help. In mapped tactical combat, the winner decides who sets up first on the map, and once all fighters are placed, gets to move them around to improve his side's situation.
Both these skills appeared at GURPS 1e. Basic says that they're usually only taught by the military, but there are exceptions to that in the modern world. Riot-trained police learn something like Tactics for tackling demonstrations, and the War Colleges that train military officers in Strategy and related skills also admit senior civil servants and occasional businessmen, at least in some countries. Expert Skill (Military Science) will provide information
about strategy and tactics, but won't substitute for them in action.
These skills are options on most templates for characters with military backgrounds, but few demand high skill levels.
Action uses Tactics for adopting the right procedures, planning fights, spotting enemies or avoiding being spotted, bodyguarding and assessing enemy plans; Strategy can be used for planning the actions of an NPC force.
DF makes Tactics compulsory on several templates, lets you use Tactics as a complementary skill to a friend's active defences and as part of Shield Mastery.
Fantasy discusses several ways of running large battles, and Roman leaders offering their own lives to the gods for victory, gaining bonuses to Strategy, Tactics and Leadership, plus weapon (but not Shield) skills;
Fantasy-Tech uses a leader's Tactics-6 as the "weapon skill" for reflective shields.
Infinite Worlds has Tactics software that gives +2 to a group, and
LTC3 uses Tactics for large-scale hunting.
Magic has an elixir that boosts both skills, and several schools of
Dungeon Magic study them.
Martial Arts allows use of Tactics to counter Feints and Ruses, in some circumstances, and to control Flurries in tournament combat.
Monster Hunters can use Tactics for estimating the time until the next attack, and for stealthy communication of battle plans. The
Power-Ups series has talents, quirks and wildcards for these skills, and
Powers and
Psionic Powers have several ways to use them with powers.
Social Engineering uses Strategy as a qualification skill for promotion within an army, and provides social means for hampering an opponent's Tactics, while
Back To School uses Tactics as an example for child prodigies, and both skills can be aided by Assistance Rolls via
Pulling Rank.
Space suggests that Tactics may be a TL skill in science-fiction settings, and the
Spaceships series has rules for both skills in space combat.
Supers has advice on precognition, Tactics rolls at the start of a fight, and tactical computers.
Tactical Shooting has far too many Tactics applications to list.
Thaumatology has magic items that provide both skills, while
Chinese Elemental Powers has earthquakes to boost Strategy, if you know they're coming.
Ultra-Tech has TL9+ software tools for both skills, and cunning Tactics are advisable against hordes of
Zombies.
In the more detailed treatment of military command in
GURPS:WWII, Strategy was a TL skill with no specialisation, making it more like "Grand Strategy", which is the overall moves and objectives of an entire war, or of a nation, empire or alliance in peacetime. The new skill of Operations was inserted between Strategy and Tactics to handle what the military calls "Operational Art", putting together tactical-level actions and their supply and support to accomplish military objectives. In 4e, Grand Strategy and Operational Art are both clearly parts of Strategy. Grand Strategy could be an additional specialisation; Operational Art could plausibly be an optional specialisation of the conventional forms. Strategy is not a TL skill, but could plausibly require TL familiarity.
Likewise, in G:WWII, Tactics was a TL skill, and required specialisation in a type of combat, although the list of specialisations was rather long: (Infantry), (Armoured), (Artillery), (Air-to-Air), (Air-to-Ground), (Naval), (Submarine), (Guerrilla), and (Police). The 4e skill is not TL-dependent, although TL familiarity would be plausible, and handles small units, at the level of personal command, probably no larger than an infantry platoon, which the military call "Minor Tactics." It's a fairly common house rule in 4e games to add alternative specialisations for quite different kinds of combat, like (Air-to-Air) and (Submarine).
Strategy for submarine forces is part of (Naval), but the thing that navies took a few years to learn is that trying to operate submarines as part of a surface formation doesn't work. The submarines can't communicate readily, and the surface forces can't tell the difference between enemy and friendly submarines. Indeed, they tend to be doubtful about the whole concept of "friendly submarines," and the submariners are no help with this at all. Strategy for submarines consists of working out where to send them to find targets, individually, and keeping them at a safe distance from your other forces.
I've had these skills on a fair number of GURPS characters, but they haven't been used much. I've mostly used them as license for exploiting experience in playing RPGs. I've quite enjoyed exploiting holes in GMs' tactical schemes, and creating simple but unexpected moves in other systems, but that's been player-level rather than character-level stuff. In the Weird War II campaign I play, the scale is either personal combat, or grand strategy, with one intermediate-scale event resolved using a wargame in a decade of play.
What have you done with these skills?