Description: Grappling means wrestling and struggling hand-to-hand.
Repeatedly in a grapple, a combatant needs to make opposed grapple checks against an opponent. A grapple check is something like a melee attack roll.
A combatant's attack bonus on a grapple check is: Base attack bonus + Strength modifier + special size modifier
Special Size Modifier: The special size modifier for a grapple check is as follows: Colossal +16, Gargantuan +12, Huge +8, Large +4, Medium-size +0, Small –4, Tiny – 8, Diminutive –12, Fine –16. Use this number in place of the normal size modifier a combatant uses when making an attack roll.
A combatant provokes an attack of opportunity from the target the combatant is trying to grapple. If the attack of opportunity deals the combatant damage, the combatant fails to start the grapple.
To start a grapple, a combatant first needs to grab and hold a combatant's target. Attempting to start a grapple is the equivalent of making a melee attack. If a combatant gets multiple attacks in a round, a combatant can attempt to start a grapple multiple times (at successively lower base attack bonuses). A monk can use his unarmed attack rate of attacks per round while grappling.
Step 1: Grab:
The combatant makes a melee touch attack to grab the target. If the combatant fails to hit the target, the combatant fails to start the grapple.
Step 2: Hold:
Make an opposed grapple check. If the combatant succeeds, the combatant has started the grapple, and the combatant deals damage to the target as if with an unarmed strike.
If the combatant loses, the combatant fails to start the grapple. The combatant automatically loses an attempt to hold if the target is two or more size categories larger than the combatant is (but the combatant can still make an attempt to grab such a target, if that's all the combatant wants to do).
Step 3: Move In:
To maintain the grapple, the combatant must move into the target's space. Moving, as normal, provokes attacks of opportunity from threatening enemies, but not from the combatant's target.
Step 4: Grappling:
The combatant and the target are now grappling.
If a combatant's target is already grappling someone else, then the combatant can use an attack to start a grapple, as above, except that the target doesn't get an attack of opportunity against the combatant, and the combatant's grab automatically succeeds. The combatant still has to make a successful opposed grapple check to deal damage and must still move in to be part of the grapple.
When a combatant is grappling (regardless of who started the grapple), the combatant can make an opposed grapple check as an attack. If the combatant wins, the combatant can do the following:
Damage A combatant's Opponent: A combatant deals damage as with an unarmed strike (1d3 points for Medium-size attackers or 1d2 points for Small attackers, plus Strength modifiers). If a combatant wants to deal normal damage, the combatant suffers a -4 penalty on the grapple check. Exception: Monks deal more damage on an unarmed strike than other combatants, and the damage is normal. However, they can choose to deal their damage as subdual damage when grappling without paying the usual -4 penalty for changing normal damage to subdual damage.
Pin: A combatant can hold an opponent immobile for 1 round. (If a combatant gets multiple attacks, the combatant can use subsequent attacks to damage the opponent. A combatant can't use a weapon on a pinned opponent or attempt to damage or pin a second opponent while holding a pin on the first.) While a combatant is pinned, opponents other than the one pinning the combatant get a +4 bonus on attack rolls against the combatant (but the combatant is not helpless).
Break Another's Pin: A combatant can break the hold that an opponent has over an ally.
Escape: A combatant can escape the grapple. A combatant can take whatever movement the combatant gets. If more than one opponent is grappling a combatant, the combatant's grapple check result has to beat all their check results to escape. (Opponents don't have to try to hold a combatant if they don't want to.)
When an opponent has pinned a combatant, the combatant is held immobile (but not helpless) for 1 round. The combatant can make an opposed grapple check as a melee attack. If the combatant wins, the combatant escapes the pin, but the combatant is still grappling.
In addition to making opposed grapple checks, a combatant has a few other options while grappling.
Weapons: A combatant can attack with a light weapon while grappling (but not while pinned or pinning). A combatant can't attack with two weapons while grappling.
Wriggle Free: A combatant can make an Escape Artist check (opposed by a combatant's opponent's grapple check) to get out of a grapple or out of being pinned (so that the combatant is just being grappled). Doing so counts as a standard action; if a combatant escapes a grapple, the combatant can also move in the same round.
Several combatants can be in a single grapple. Up to four combatants can grapple a single opponent in a given round. Opponents that are one size category smaller than a combatant count for half, opponents that are one size category larger than a combatant count double, and opponents two or more size categories larger count quadruple.
Additional enemies can aid their friends with the aid another action.
While a combatant is grappling, that combatant's ability to attack others and defend a itself is limited.
No Threatened Area: A combatant doesn't threaten any area while grappling.
No Dexterity Bonus: A combatant loses it's Dexterity bonus to AC (if a it has one) against opponents a it isn't grappling. (A combatant can still use the bonus against opponents the combatant is grappling.)
