OGL content from Swords and Wizardry ( https://www.d20swsrd.com/for-players/combat#TOC-Specific-Situations )
Second Rank (or Spears and Polearms)
Spears and polearms in the second rank of a battle formation can attack by reaching through the first rank.
Casting a spell starts at the beginning of the combat round. Spells cannot be cast if the caster is in melee combat; although the Referee might rule that even if the caster is within ten feet of an opponent, if blows have not been traded, then a spell can be cast. Wands and staffs are not subject to the restriction at all; they can cast their magic during melee combat. If the spellcaster suffers damage while casting a spell, the spell is lost. When the spell actually takes effect depends on which Combat Sequence Method is being used.
A weapon may be used to beat down, rather than kill, an opponent. When the player desires, damage infl icted by a character can be composed of half “real” damage and half “subdual” damage. Subdual damage does not kill, and such points are recovered at a rate of 1 hp per hour. If an opponent’s hit points, including the subdual damage, fall to zero, the opponent is knocked unconscious rather than killed, unless the real damage actually reduces real hit points to zero, in which case the opponent is killed accidentally!
Not all monsters may be subdued. Generally only humanoids and special creatures such as dragons will be subject to such attacks.
Characters and monsters will hide behind things, stand on things, lie prone, fight from higher ground, shoot arrows from within concealing mists or tree branches, and take every possible advantage of the combat terrain. The Referee will assign bonuses and penalties for terrain features. Most such bonuses will only be +/- 1 or 2, depending on the degree of cover or the benefit of higher ground. Trying to hit someone through an arrow slit in a castle wall might have a penalty of –4 (as suggested in the Holmes Basic Set in 1977). Remember, however, that the penalty to hit an invisible opponent is only -4, so +/- 4 is about the outside limit for terrain adjustments on the to-hit roll.
Two-weapon Fighting and Two-handed Weapons
Just as shields improve armor class by 1, fighting two-handed grants a +1 to damage rolls (except for weapons that can only be used two-handed, where this is already taken into account in the weapon’s damage), and fighting with a weapon in each hand gives a +1 to hit, but only in rounds in which the attacker won the initiative roll. (Note that fighting with two weapons does not actually give two separate attacks; it just increases the likelihood of landing a successful blow.)