How can we implement this into an existing AD&D framework? Well, in the AD&D weapons table, each weapon has it's length. For simplicity's sake, we can break the melee weapon reach bands as follows:
PUNCHING/ HAND AXE/ SHORT SWORD
For realism's sake, I suggest that you use the AD&D 1st Edition Weapon vs Armor table. Use it only against the opponents actually wearing armor. The attacker gets the full melee bonus when he strikes at the reach appropriate to his weapon so as to develop the optimal kinetic energy for the blow. When the attacker is running up to and striking the opponent outside the strike range, he loses the to hit bonus and the penalty is multiplied by 1.5. If the attacker is forced to step back, he takes a -1 To Hit penalty. If the attacker is forced to fight at one reach band closer than the weapon range, the To Hit Penalty drops to -3. At 2 reach bands closer, if the weapon can be used at all, the penalty increases to -5 To Hit. A pole arm might not be useful at all at spear range if there is not room to push back the excess weapon shaft. A spear becomes a cudgel held with two hands and doing 1d4 damage at the fencing reach. A Two handed sword can be used with both hands (if the attacker wears gauntlets), also as an improvised cudgel.
Let's examine a situation, where a swordsman is advancing on a spearman. Then melee starts at the Pike range, with the attacker just out of range. Each of them rolls to hit. If the spear hits, the attacker does damage AND keeps the advancing swordsman at the distance. If the swordsman scores a hit, he gets to close the distance to the spear reach. If the swordsman misses, he does not close the distance. At the spear range, the swordsman advances only if he scores a hit and the spearman misses. If both score the hit, the spearman hits, swordsman mitigates the damage if he hit better than the spearman. If the spearman made his to hit roll by 2 and the swordsman made his to hit roll by 5, he subtracts 3 from the spear damage. Also, the swordsman advances at the spear reach if he hits twice in a row, regardless of whether the spearman scores a hit that second time. Finally, at the great sword range, the spearman can retreat if he chooses, or fight at a penalty, the swordsman has a choice of whether attacking the spearman (finally) or parrying the spear. The swordsman will fight at optimal strength (no penalties) so far as he is parrying the spear. Once the swordsman closes to his optimal strike range, swordsman's bonuses kick in, while the spearman is either retreating or fighting at a severe disadvantage.
Keep in mind that if you use the weapon speed factors in the AD&D weapon tables, the swordsman can actually strike twice, if the spearman is slow or unlucky, and the soldier using the short sword or a dagger at the close or grappling range can strike the spearman three or four times, potentially doing massive amounts of damage to the unfortunate spearman.
In the next installment we will find out about the timing, weapon speed, and initiative and how these translate into multiple strikes for the attacker.