How to Play D&D

Between encounters, your characters explore the world. You make decisions about which way your character travels and what he or she tries to do next. Exploration is the give-and-take of you telling the DM what you want your character to do, and the DM telling you what happens when your character does it. For example, let’s say the player characters have just climbed down into a dark chasm. The DM tells you that your characters see three tunnels leading from the chasm floor into the gloom. You and the other players decide which tunnel your characters
venture into first, and you tell the DM which way your characters are heading. That’s exploration.

You might try almost anything else: finding a place to hide and set an ambush in case monsters come by, shouting “Hello, any monsters here?” as loud as you can, or searching the chasm floor carefully in case there’s anything interesting lying amid the boulders and
moss. That’s all exploration, too.

Decisions you make as you explore eventually lead to encounters. For example, one tunnel might lead into a nest of hungry gricks—if you decide to go that way, your characters are heading into a combat encounter. Another tunnel might lead to a door sealed by a magic lock that you have to break through—a noncombat encounter.

While exploring a dungeon or other adventure location, you might try to do any of the following actions:
✦ Move down a hallway, follow a passage, cross a room
✦ Listen by a door to determine if you hear anything on the other side
✦ Try a door to see if it’s locked
✦ Break down a locked door
✦ Search a room for treasure
✦ Pull levers, push statues or furnishings around
✦ Pick the lock of a treasure chest
✦ Jury-rig a trap

The Dungeon Master decides whether or not something you try actually works. Some actions automatically succeed (you can move around without trouble, usually), some require one or more die rolls, called checks (breaking down a locked door, for example), and some simply can’t succeed. Your character is capable of any deeds a strong, smart, agile, and well-armed human action hero can pull off. You can’t punch your way through a door of 3-inch-thick iron plate with your bare hands, for example—not unless you have powerful magic to help you out!

How do you know if your sword-swing hurts the dragon, or just bounces off its iron-hard scales? How do you know if the ogre believes your outrageous bluff, or if you can swim the raging river and reach the other side?

All these actions depend on very basic, simple rules: Decide what you want your character to do and tell the Dungeon Master. The DM tells you to make a check and figures out your chance of success (a target number for the check).

You roll a twenty-sided die (d20), add some numbers, and try to hit the target number determined by the DM. That’s it!

(Simplified)
1. Roll a d20. You want to roll high!
2. Add all relevant modifiers.
3. Compare the total to a target number.

If your check result is higher than or equal to the target number, you succeed. If your check result is lower than the target number, you fail. If your check succeeds, you determine the outcome. If your check was an attack, you roll damage. If it was a check to see if you managed to jump across a pit, your check result determines how far you jumped. If you succeed on a check when you’re trying to hide, the monsters don’t see you.

There’s a little more to it than that, but the core mechanic governs all game play. All the rest of the rules in the book are extensions and refinements of this simple mechanic.

In addition to the core mechanic, three principles are at the heart of the DUNGEONS & DRAGONS game. Many other rules are based on these assumptions.

Simple Rules, Many Exceptions
Every class, race, feat, power, and monster in the D&D game lets you break the rules in some way. These can be very minor ways: Most characters don’t know how to use longbows, but every elf does. These exceptions can also appear in very significant ways: A swing with a sword normally does a few points of damage, but a high-level fighter can use a power that can fell multiple monsters in a single blow. All these game elements are little ways of breaking the rules—and most of the books published for the D&D game are full of these game elements.

Specific Beats General
If a specific rule contradicts a general rule, the specific rule wins. For example, a general rule states that you can’t use a daily power when you charge. But if you have a daily power that says you can use it when you charge, the power’s specific rule wins. It doesn’t mean that you can use any daily power when you charge, just that one.

Always Round Down
Unless otherwise noted, if you wind up with a fraction as the result of a calculation, round down even if the fraction is 1/2 or larger. For instance, this rule comes into play whenever you calculate one-half your level: If your level is an odd number, you always round down to the next lower whole number.

1. Determine surprise. The DM determines whether any combatants are surprised. If any combatants notice enemy combatants without being noticed in return, the aware combatants gain a surprise round.

2. Establish positions. The DM decides where the combatants are positioned on the battle grid. For example, if the PCs have just opened a door into a room, the DM might draw or arrange a depiction of the door and the room on the battle grid and then ask the players to arrange their miniatures near the door. Then the DM places miniatures that represent the monsters in the room.

3. Roll initiative. Everyone involved in a combat encounter rolls initiative, determining the order of combatants’ turns. You roll initiative only at the beginning of a combat encounter.

4. Take surprise round actions. If any combatants gained a surprise round, they act in initiative order, each one taking a single action. (Surprised combatants take no actions during the surprise round.) The surprise round then ends, and the first regular round of combat begins.

5. Take turns. In initiative order, every combatant takes a turn, which includes various actions. (Combatants can also take certain actions on one another’s turns.)

6. Begin the next round. When every combatant has had a turn, the round ends. Begin the next round with the combatant who has the highest initiative.

7. End the encounter. Repeat steps 5 and 6 until the the combatants on one side are captured, fleeing, unconscious, or dead. The encounter ends when the other side then takes a short rest or an extended rest.

To determine a combat encounter’s initiative order, roll initiative. To do so, make a Dexterity check.

Roll 1d20 and add the following:

✦ One-half your level

✦ Your Dexterity modifier

✦ Any bonuses or penalties that apply

The result is your initiative for this encounter. When combatants have the same initiative, the combatant with the higher initiative bonus (the total of one-half your level, your Dexterity modifier, and any bonuses) goes before the other. If their bonuses are the same, they can roll a die or flip a coin to break the tie.

✦ Standard Action: Standard actions are the core of combat. You can normally take one standard action on your turn. Examples: most attack powers, charging an enemy, using your second wind.

✦ Move Action: Move actions involve movement from one place to another. You can normally take them only on your turn. Examples: walking, shifting.

✦ Minor Action: Minor actions are enabling actions, simple actions that usually lead to more exciting actions. You can normally take them only on your turn. Examples: pulling an item from a pouch or a sheath, opening a door or a treasure chest, picking up an item in your space or in an unoccupied square within reach.

✦ Free Action: Free actions take almost no time or effort. You can take as many free actions as you want during your or another combatant’s turn. The DM can restrict the number of free actions in a turn. Examples: speaking a few sentences, dropping a held item, letting go of a grabbed enemy.

Triggered Action Types:

Two action types—opportunity actions and immediate actions—require triggers. A trigger is an action, an event, or an effect that allows you to use a triggered action. (Some powers require a trigger but are free actions or aren’t actions at all.)

✦ Trigger: Opportunity actions allow you to take an action in response to an enemy letting its guard down. The one type of opportunity action that every combatant can take is an opportunity attack. Opportunity attacks are triggered by an enemy leaving a square adjacent to you or by an adjacent enemy making a ranged attack or an area attack.

✦ Once per Combatant’s Turn: You can take no more than one opportunity action on each other
combatant’s turn. You can’t take an opportunity action on your own turn.

✦ Interrupts Action: An opportunity action interrupts the action that triggered it.

There are two kinds of immediate actions: interrupts and reactions. Certain rules govern all immediate actions, whether they’re immediate interrupts or immediate reactions.

✦ Trigger: Each immediate action—usually a power—defines its specific trigger. The one type of
immediate action that every combatant can take is a readied action.

✦ Once per Round: You can take only one immediate action per round, either an immediate interrupt or an immediate reaction. If you haven’t taken an immediate action since the end of your last turn, you can take one when a trigger allows you to. You can’t take an immediate action on your own turn.

✦ Interrupt: An immediate interrupt lets you jump in when a certain trigger condition arises, acting before the trigger resolves. If an interrupt invalidates a triggering action, that action is lost. For example, an enemy makes a melee attack against you, but you use a power that lets you shift away as an immediate interrupt. If your enemy can no longer reach you, the
enemy’s attack action is lost.

✦ Reaction: An immediate reaction lets you act in response to a trigger. The triggering action, event, or condition occurs and is completely resolved before you take your reaction, except that you can interrupt a creature’s movement. If a creature triggers your immediate reaction while moving (by coming into range, for example), you take your action before the creature finishes moving but after it has moved at least 1 square.

An immediate reaction might interrupt other actions a combatant takes after its triggering action. For example, if a power lets you attack as an immediate reaction when an attack hits you, your action happens before the monster that hit you can take any other action. If a monster has a power that lets it make two attack rolls against you as a standard action, and the first one hits, you can use an immediate reaction before the next attack roll.