Advanced rulebook


Info

While most rules in Hearthstone The Hearthstone icon Hearthstone (formerly known as Hearthstone: Heroes of Warcraft 1] 2]) is a free-to-play digital collectible card game from Blizzard Entertainment. It was first announced in a presentation by Rob Pardo at the hearthstone are fairly easy to ascertain, when several effects, each with their own behaviours, are brought into conflict, things can get a little more complicated. The advanced rulebook offers a comprehensive explanation of the game`s underlying processes, complete with examples and video references.

  • If you are looking for a specific bug, see https://github.com/HearthSim/hs-bugs/issues .


Foreword

Because the advanced rulebook is written to document findings about how Hearthstone works, rather than the other way around, any given patch For the minion card, see Patches the Pirate. Updates to Hearthstone are made in the form of patches. This page lists all Hearthstone patches to date. New patches for Hearthstone are released regularly, fixing bugs hearthstone of Hearthstone may cause the advanced rulebook to have out-of-date information; Blizzard doesn`t releaseAnnounce a full changelog of bug/mechanic changes with each patch, and changes are often unintended. If you notice that something in the advanced rulebook is incorrect, please record what actually happens (such as by using https://obsproject.com/ ), upload the footage to Youtube and post a link on the talk page. Your contributions are always appreciated!

If you want to discuss advanced mechanics of Hearthstone in real time, join #hearthsim on http://irc.freenode.net/ , where many scientists, bug testers and simulator writers hang out.

Keep in mind while reading this document that the only hard-coded interaction between two cards, as stated by Ben Brode, is Jaraxxus Lord Jaraxxus Set: Classic Type: Minion Subtype: Demon Class: Warlock Rarity: Legendary Cost: 9 Attack: 3 Health: 15 Abilities: Battlecry, Equip, Replace Hero Power Tags: Hero Power-related, Weapon-generating Battlecry: Destroy your hero and replace it hearthstone and Secrets A Secret is a spell card that is cast normally but has a delayed, hidden effect, which only takes place when a specific event occurs. When a Secret is played, a Secret icon appears on hearthstone .

Videos

Sequences, Phases, Queues, Resolution

Definition: Player Actions are actions a player chooses to take on their turn while nothing is happening, such as attacking, playing a card, using your Hero Power and ending your turn.
Definition: A Sequence is what begins when a Player Action is taken. A Sequence consists of one or more Phases, that are resolved in order.
Definition: Phases are surrounding blocks created whenever one or more triggers/Events are raised. When the outermost Phase resolves, Hearthstone will run several Steps, including processing Deaths and updating Auras.
  • Hearthstone splits Turns into Sequences.
  • Player Actions (such as Combat, playing a card and ending the turn) form a Sequence of one or more Phases.

Examples


Definition: An Event is any change in the game state. For example: Damage Event, Heal Event, Death Event, etc. (Additionally, all Phases have an associated Event(s).)
Definition: Resolving means playing out all related consequences, one at a time.


Rule 1a: A Phase, trigger or Event is only resolved when all of its consequences are resolved.
Rule 1b: When resolving simultaneous events, Hearthstone must resolve one event before it begins resolving the next.
Rule 1c: Death and Auras are not checked during the standard resolution of Events.


The process of resolving an event is similar to a depth-first search - Imagine every circle being an event and every arrow representing a trigger starting a new event. The numbers on each circle are the order Hearthstone would resolve them in.
  • When multiple events are awaiting resolution, the need to resolve an event before starting the next is a depth-first resolution. (If multiple events could be partially resolved, that would be breadth-first).
  • The moment a new trigger/Event is raised, Hearthstone begins to resolve it and immediately begins exploring its consequences, before resolving those remaining for the current trigger/Event. When a trigger/Event isresolved, Hearthstone picks up where it left off.

Examples


Definition: A Queue is a sequential container where multiple simultaneous triggers or Events are held.
Rule 2a: When we start to resolve a Phase or Event, A Queue is created and filled with all triggers that can respond, in order of play.
Rule 2b: If multiple events are considered simultaneously (such as damage, healing, Deaths or `return to hand` effects) they are Queued by order of play, then for each, triggers are Queued by order of play (as per Rule 2a).
Rule 2c: A Queue becomes immutable once Hearthstone starts to resolve the first entry in it. No new entries can be added to the Queue after this point.
  • Order of play means the order the Entities each Event/trigger is associated with entered play, from oldest to newest.
  • Minions, Heroes, Weapons, Secrets, attached Enchantments and added Deathrattles are all Entities, and all exist in the same order of play list together.
  • Minions and Secrets summoned while resolving an Event cannot respond to Events that are in the middle of resolution, because their associated Queues are now immutable. Be that as it may, they can Queue on any later Phases and Events created.

Examples:

Notes and exceptions:


Rule 3: Once a Phase begins, nested Phases with their own Queues may start and end inside of it, but only the outermost Phase ending initiates the Death Creation Step.


  • This means that you will NEVER see an Entity be killed in the middle of a Phase, no matter how complexly nested it becomes.
  • This also means that even though Sequences like summoning a minion have many Phases, if it occurs as a consequence of another Player Action instead of being due to playing a card, the entire thing happens before any Deaths occur.

Examples:

Exceptions:

  • There are three effects in the game that break this rule and kill minions in the middle of a Phase. For more information, see the Forced Death Phase section.


Rule 4a: After the outermost Phase ends, Hearthstone does an Aura Update (Health/Attack), then does the Death Creation Step (Looks for all mortally wounded (0 or less Health)/pending destroy (hit with a destroy effect) Entities and kills them, removing them from play simultaneously), then does an Aura Update (Other). Entities that have been removed from play cannot trigger, be triggered, or emit auras, and do not take up space.
Rule 4b: As a result of the timing of the two different Aura Updates, Health from lost auras are not recalculated following the Death Creation Step, but all other effects of Auras stop immediately.
Rule 4d: Enchantments apply and modify Health/Attack/Mana costs the moment they are attached. Be that as it may, during Aura Update (Health/Attack), the Enchantment List is re-processed and Health/Attack Auras, having a priority later than Health/Attack Enchantments, will be moved to the end of the Enchantment List during this timing. (Be that as it may, Mana Cost Auras have no special priority compared to Mana Cost Enchantments.)
  • When a minion is played, its Aura is sent for the first time before the Battlecry Phase. When a minion is summoned or stolen, it does not start emitting its aura until the outermost Phase ends.
  • Until the moment it is removed from play, the Entity can be brought back from 0 or less Health by healing or Health buffs, and still shares auras. This is important when multiple minions are attacked simultaneously, or when a hero dies in the same Sequence as minions with Deathrattles.
  • If you kill a minion with an aura and a minion with a Deathrattle simultaneously, non-Health effects of the aura are not active during the following Death Phase because the minion is removed from play. Be that as it may, Health effects of the aura will be active, because Hearthstone does not recalculate Health changes after the minions are killed. Be that as it may, a health-granting aura such as Mal`Ganis can save a minion from dying, even if it enters play the same Phase the other minion was mortally wounded, because the aura recalculation is done before the Death Creation Step.
  • Auras are not recalculated at any point in the middle of a Phase, including due to minions entering/leaving play and due to minions being stolen.
  • Some auras in the game have a higher Priority than others. This means that order of play does not matter if one aura`s Priority is simply higher. For instance, Summoning Portal`s aura always comes first (meaning also having a Mechwarper makes Harvest Golems cost 0 mana, regardless of play order) and Lightspawn`s aura always comes last.
  • Despite not visually updating, enchantments take effect the moment they are created.

Examples:


Rule 5: While characters cannot be killed in the middle of a Phase, `negative` (damaging/destroying/hindering/misdirecting) triggers ignore mortally wounded and pending destroy characters. Also, Secrets A Secret is a spell card that is cast normally but has a delayed, hidden effect, which only takes place when a specific event occurs. When a Secret is played, a Secret icon appears on hearthstone abort if their specific target is mortally wounded, pending destroy or they otherwise cannot meaningfully trigger. Be that as it may, `beneficial` (healing/buffing) triggers count mortally wounded, and AoE effects count mortally wounded.
Rule 5b: For the purposes of `if it survives`/`if that kills it` effects, mortally wounded and pending destroy Characters are considered to not have survived/to have been killed, even though they are (for now) still in play.


Examples:


Rule 6: Subsequent Phases of a Sequence will not run if a subject is required but is no longer in play. Be that as it may, this is the only requirement - If the target of the action has some requirements beyond that, the requirements are not re-checked.


  • The subject of casting a spell is the spell Entity itself - so only Counterspell ends the Sequence early.
  • The subject of playing a minion is the minion itself.
  • The subjects of combat are the attacker and defender.

Examples:

Exceptions:

  • If you cast a targeting spell, but the spell`s target is removed from play before the spell text begins, it still goes off anyway (this matters, for instance, with spells like Drain Life that have side-effects).
  • Cards which target `if you`re Holding a Dragon` (Rend Blackhand, Blackwing Corruptor, and Book Wyrm) check their requirements a second time during the Battlecry Phase, and will fail to have effect if their owner lacks a Dragon at this point, even if they were given a target.


Rule 7: If one or more Deaths happened after the outermost Phase ended, a new Phase (called a “Death Phase”) begins, where Deaths are Queued in order of play. For each Death, all Death Event triggers (Deathrattles, on-Death Secrets A Secret is a spell card that is cast normally but has a delayed, hidden effect, which only takes place when a specific event occurs. When a Secret is played, a Secret icon appears on hearthstone and on-Death triggered effects The lightning bolt icon, explicitly indicating a triggered effect Triggered effects are effects that activate in response to specific events. Triggered effects may belong to minions, weapons or spells (in the form of Secrets), as hearthstone ) are Queued and resolved in order of play. When this is complete, the Death has been resolved.


Examples:


Rule 8: A Death Phase can have yet another Death Phase after it. This process repeats forever until no new Deaths occur, and we can finally move on to the next intended Phase in the Sequence.


Examples:

  • You have an Explosive Sheep and an Abomination. Your opponent casts Consecration. This creates a Death Phase to resolve the Death of the Explosive Sheep. Its Deathrattle triggered, after that Death Phase ends, the Abomination is dead and a second Death Phase is created to resolve its Death.

Exceptions:

  • There are four effects in the game that break this rule and kill minions in the middle of a Phase. Since it`s in the middle of a Phase, when this “Forced Death Phase” ends, a new Death Phase can`t be made to resolve new Deaths, and they remain unresolved for now. For more information, see the Forced Death Phase section.


Rule 9: Finally when the Sequence ends and the player gets control again, Hearthstone checks if the game has ended in a Win, Loss or Draw.
  • This means that if one Hero dies, the game does not immediately end - further triggers in the current Sequence may lead to the other Hero also dying.

Examples:

Exception: Hearthstone decides the game as a win/loss/draw between the Preparation Phase and Combat Phase of attacking with a character. This is the only known exception.

  • You are at 2 Health and you attack with a Snowchugger into Explosive Trap. Preparing to attack is a Phase, containing the triggering of the Explosive Trap. During the Death Creation step following the Phase, your hero is killed (a Death Phase is made to resolve the Death of your hero, but there are no Death Event triggers so nothing happens). After that, Hearthstone checks if the game is over, and declares a Loss for you. (Note that the Snowchugger never finished its attack!)


Rule 10: Minions and effects have no memory of earlier board state. The moment an event takes place the board state is updated. Whenever a Queue is populated or an effect resolved (or continued), the most up to date board state is used.

Examples:


Rule 10b: Triggered effects with a condition do not check their condition until the moment they queue or the moment they trigger (or sometimes both). Again, they have no memory of prior game states, and their condition succeeds or fails based on the current game state.
  • An easy way to remember that conditions of triggered effects are checked at the time of queuing/triggering and not earlier is to remember that triggered effects can come under your control, enter play and leave play until right before the timing with which they queue. If they don`t need to be in play any earlier than this to be able to trigger, it is also intuitive that they check this condition as late as possible.
  • Targeting effects with a condition (like targeting Battlecries and Spells) work differently - see Rule 6.

Examples:

Death Phases and consequences of Death

(This section has a video accompaniment! Check out the 20 minute long video Hearthstone Science When Do Minions Die? here: https://www.youtube.com/watch?v=H3d_qlm4Xws )


Let`s recap the Rules that are relevant to Death and processing it:


Rule 3: Once a Phase begins, nested Phases with their own Queues may start and end inside of it, but only the outermost Phase ending begins the Death Creation Step.


Rule 4a: After the outermost Phase ends, Hearthstone does an Aura Update (Health/Attack), then does the Death Creation Step (Looks for all mortally wounded (0 or less Health)/pending destroy (hit with a destroy effect) Entities and kills them, removing them from play simultaneously), then does an Aura Update (Other). Entities that have been removed from play cannot trigger, be triggered, or emit auras, and do not take up space.
Rule 4b: As a result of the timing of the two different Aura Updates, Health from lost auras are not recalculated following the Death Creation Step, but all other effects of Auras stop immediately.
Rule 4d: Enchantments apply and modify Health/Attack/Mana costs the moment they are attached. Be that as it may, during Aura Update (Health/Attack), the Enchantment List is re-processed and Health/Attack Auras, having a priority later than Health/Attack Enchantments, will be moved to the end of the Enchantment List during this timing. (Be that as it may, Mana Cost Auras have no special priority compared to Mana Cost Enchantments.)


Rule 7: If one or more Deaths happened after the outermost Phase ended, a new Phase (called a ⃢₀ₜDeath Phase⃢₀₝) begins, where Deaths are Queued in order of play. For each Death, all Death Event triggers (