Tactics and strategy take place at three levels: The exploration level, the squad combat level, and the level of actions in combat.
- OSR is pretty unique among roleplaying games in being concerned about the exploration level.
- Many roleplaying games deal with the squad combat level, though only in the simple way of everyone deciding who they are going to attack.
- At the level of actions of individual combatant there are rulesets like Pathfinder, where you can optimize your character to be good at (say) tripping and dealing damage, and then in combat situations you can select which of them is more useful, or claim the game is poorly designed if neither is. There are also Burning wheel and The riddle of steel, which have more interesting combat minigames.
Here is a set of principles for adding level three to OSR play, without complicated lists of maneuvres. This same approach should work with any traditional roleplaying game which has characters acting as individuals in combat and their actions resolved separately. Tunnels and trolls requires a modified approach.
The purpose is not to reward players of describing cool stunts; but rather to reward player skill in coming up with good ideas and judging risk, which should naturally lead to more interesting combats. A hopeful side effect is an interest in (medieval) combat and the desire to find out more about it.
Player states what their character is going to do. Someone, typically the referee, suggests how it should be mechanically resolved, so that the result is as realistic (within the setting and genre) as possible. Play group as a whole agrees to the suggestion or suggests a better one.
Over longer term play the solutions to common actions will probably become standardized, but this is not necessary.
This is precisely the same core mechanic as in all OSR play. Combat is in no way different from other parts of the game, at this level.
An example with a giant
You are playing an adventurer wearing gambeson, with a buckler hanging from your belt and a sheathed sword. Your group is surprised by a male giant, who runs out of the woods and smashes one of you allies, and is now looking for the next one to smash. What do you do?
Drawing the sword would take some time (say, -2 or -5 to next action, or some lost initiative if one uses individual initiative), but the buckler is pretty much instant to grab. Approaching the giant with either would be quite dangerous, as it has better reach and is prepared to attack; say -10 to attack roll if trying that. (An alternative would be some kind of attack of opportunity the giant can make; one can also let the player decide, here, how risky an approach they take.) On the other hand, waiting for the giant to (try to) smash someone else and running in after that would not carry such risks, but would give initiative to the giant and maybe cause another death. One might want to run between the giant’s legs and smash its crotch with the buckler; this could be a normal attack, and on success it causes hit point loss (not serious wounds, though) and forces the giant to save or be stunned for a round or two. Or, if the sword is drawn, stab the giant with that while running past, which would be a normal attack.
An example against a human
You are facing a swordsman. You have only a rondel dagger and a throwing knife. Both of you are unarmoured.
You might want to try to finish the combat with a single throwing knife – if it works, that is it, but if not, you are facing a swordsman while equipped with only a dagger, which is not a good situation. Maybe you pretend to throw the knife to see how the swordsman reacts. Or maybe you move close, and while almost as sword range, throw the knife (at a penalty or without a bonus) and charge in at the same time, trying to close the distance while your foe reacts to the knife. The enemy would have to choose between blocking/dodging the knife (while allowing you to close in), or hoping you fail at the throw and striking at you as you approach. On an excellent success (natural 20, margin of success 10+, etc.) they might get to do both.
If you miss with knife, then attacking a swordsman with only a dagger is similar to the situation with the giant, though hopefully less dire.
Whoever has initiative, decides how they will approach the situation. Others react, which might or might not give them choices. Above, the giant did not get to make any choices, while the swordsman did against the combined throw and charge.
I would suggest using individual initiative with this approach.
When is this appropriate
This type of resolution puts focus on the details of the combat. Some people might not want to do so, in which case they should not use this approach. Abstraction and focusing elsewhere is a valid choice, as always.