Intro to the fine art of grappling, starting with some basic mechanics

Simply put, grappling puts two or more combattants at a severe disadvantage. While in a grappled state a combatant loses his Dexterity bonus to AC, may only use light or smaller weapons, cannot move without breaking the grapple, and threatens nothing for the purposes of attacks of opportunity.

While grappling, you pretty much have x options:

• Deal Damage by attacking or grappling to damage. Attacks are limited to light weapons (at least one size category smaller than the attacker).
• Cast Spellsthough at a disadvantage. Only spells with no somatic (gesture) components are allowed, and even then a concentration check has to be made (as if casting defensively) to get the spell off at all.
• Pin your opponent, making them utterly immobile for 1 round.
• Break Pin and thereby negate a pinned state.
• Escape Grapple with either an opposed grapple check or an escape artist check, ending the grappled state.

Initiating a grapply starts with a melee touch attack (normally AC10 + dex modifier, though magic can come into play). This attack provokes an attack of opportunity, and if the attack of opportunity lands, the grapple attempt fails.

Grappling checks are simply Base Attack Bonus + Strength Bonus + Size Modifier (+/- 4 per size category). Make an opposed Grapple check between the involved combatants. If the attacker wins, the grapple is on.

Once grappled, the four options above are all the combatants have, though the attacker can choose to drop the grapple on his own turn if he pleases.

Two opponents who are grappling occupy the same space, with the attacker moving into the space occupied by the object of the attack. If this extra movement would normally cause an attack of opportunity, everybody but the grappled defender gets their free shots off as usual.

Overall, it looks pretty bad, and consequently a lot of people don’t even consider grappling when they enter a combat situation.