Player Restrictions

Player restrictions are effects that say a player cannot do something: draw, Summon, enter the Battle Phase, activate certain effects, add cards from the Deck to the hand, discard as cost, and so on.

Most of these are field effects with EFFECT_FLAG_PLAYER_TARGET. Their SetTargetRange values are player flags, not card locations.

The Basic Player Lock Shape

Lava Golem (c102380.lua) prevents its owner from Normal Summoning or Setting for the rest of the turn after using its Special Summon procedure:

local e1=Effect.CreateEffect(c)
e1:SetType(EFFECT_TYPE_FIELD)
e1:SetCode(EFFECT_CANNOT_SUMMON)
e1:SetProperty(EFFECT_FLAG_PLAYER_TARGET+EFFECT_FLAG_OATH)
e1:SetReset(RESET_PHASE+PHASE_END)
e1:SetTargetRange(1,0)
Duel.RegisterEffect(e1,tp)

local e2=e1:Clone()
e2:SetCode(EFFECT_CANNOT_MSET)
Duel.RegisterEffect(e2,tp)

The key pieces are:

Piece	Meaning
EFFECT_TYPE_FIELD	The effect applies to the duel state, not only the handler.
EFFECT_FLAG_PLAYER_TARGET	SetTargetRange should be read as affected players.
SetTargetRange(1,0)	Affect the player who controls/registered the effect.
Duel.RegisterEffect(e,tp)	Register a temporary player effect for player tp.
EFFECT_FLAG_OATH	The restriction is an oath-style restriction that should not disappear just because the card leaves.

For player-target field effects, SetTargetRange(1,0) means the registering player, and SetTargetRange(0,1) means that player's opponent. This is different from ordinary card-location field effects, where the values are location masks such as LOCATION_MZONE.

Temporary Cost Restrictions

Some effects apply a restriction as part of paying a cost. Truth Reinforce (c10118318.lua) says you cannot conduct your Battle Phase the turn you activate it:

function s.cost(e,tp,eg,ep,ev,re,r,rp,chk)
    if chk==0 then return Duel.GetActivityCount(tp,ACTIVITY_BATTLE_PHASE)==0 end
    local e1=Effect.CreateEffect(e:GetHandler())
    e1:SetType(EFFECT_TYPE_FIELD)
    e1:SetCode(EFFECT_CANNOT_BP)
    e1:SetProperty(EFFECT_FLAG_PLAYER_TARGET+EFFECT_FLAG_OATH)
    e1:SetTargetRange(1,0)
    e1:SetReset(RESET_PHASE+PHASE_END)
    Duel.RegisterEffect(e1,tp)
end

The chk==0 branch checks whether the player has already performed the forbidden action. The cost branch registers the restriction for the rest of the turn.

Use this pattern for "you cannot X the turn you activate this card/effect" text:

1. Check the relevant activity counter in the cost or activation check.
2. Register a temporary oath restriction when the cost is paid.
3. Reset it at the End Phase.

Continuous Player Restrictions

Some restrictions stay active while the handler remains in its range. Protector of the Sanctuary (c24221739.lua) prevents the opponent from drawing outside the Draw Phase:

local e1=Effect.CreateEffect(c)
e1:SetType(EFFECT_TYPE_FIELD)
e1:SetProperty(EFFECT_FLAG_PLAYER_TARGET)
e1:SetCode(EFFECT_CANNOT_DRAW)
e1:SetRange(LOCATION_MZONE)
e1:SetTargetRange(0,1)
e1:SetCondition(s.con)
c:RegisterEffect(e1)

function s.con(e)
    return Duel.GetCurrentPhase()~=PHASE_DRAW
end

Because this effect is registered on the monster, it only applies while the monster is in its SetRange. It does not use Duel.RegisterEffect, and it does not need an End Phase reset.

Activation Restrictions

To stop a player from activating certain effects, use EFFECT_CANNOT_ACTIVATE with a value function:

local e1=Effect.CreateEffect(c)
e1:SetType(EFFECT_TYPE_FIELD)
e1:SetProperty(EFFECT_FLAG_PLAYER_TARGET)
e1:SetCode(EFFECT_CANNOT_ACTIVATE)
e1:SetRange(LOCATION_MZONE)
e1:SetTargetRange(0,1)
e1:SetValue(s.aclimit)
e1:SetCondition(s.actcon)
c:RegisterEffect(e1)

function s.aclimit(e,re,tp)
    return re:IsHasType(EFFECT_TYPE_ACTIVATE)
end

Ancient Gear Beast (c10509340.lua) uses this shape while it is attacking. The value function receives the effect being checked, so it can inspect the activation type, card type, category, owner, or other effect data.

Hand And Deck Access Restrictions

Several restrictions use a target function to decide which attempted card movement is forbidden.

Deck Lockdown (c1149109.lua) prevents both players from adding cards from the Deck to the hand:

local e1=Effect.CreateEffect(c)
e1:SetType(EFFECT_TYPE_FIELD)
e1:SetCode(EFFECT_CANNOT_TO_HAND)
e1:SetRange(LOCATION_SZONE)
e1:SetProperty(EFFECT_FLAG_PLAYER_TARGET)
e1:SetTargetRange(1,1)
e1:SetTarget(aux.TargetBoolFunction(Card.IsLocation,LOCATION_DECK))
c:RegisterEffect(e1)

Greed Goblin (c425934.lua) prevents discarding as cost:

local e1=Effect.CreateEffect(c)
e1:SetType(EFFECT_TYPE_FIELD)
e1:SetProperty(EFFECT_FLAG_PLAYER_TARGET)
e1:SetRange(LOCATION_MZONE)
e1:SetTargetRange(1,1)
e1:SetCode(EFFECT_CANNOT_DISCARD_HAND)
e1:SetTarget(s.target)
e1:SetValue(1)
c:RegisterEffect(e1)

function s.target(e,dc,re,r)
    return r&REASON_COST==REASON_COST
end

These target callbacks are not Chain target functions. They are restriction filters called by the engine while it checks whether an attempted action is allowed.

Phase Skips

Skipping a future phase is also a player-targeted field effect. Offerings to the Doomed (c19230407.lua) destroys a monster, then skips your next Draw Phase:

local e1=Effect.CreateEffect(e:GetHandler())
e1:SetType(EFFECT_TYPE_FIELD)
e1:SetProperty(EFFECT_FLAG_PLAYER_TARGET)
e1:SetCode(EFFECT_SKIP_DP)
e1:SetTargetRange(1,0)
if Duel.GetTurnPlayer()==tp and Duel.GetCurrentPhase()==PHASE_DRAW then
    e1:SetReset(RESET_PHASE+PHASE_DRAW+RESET_SELF_TURN,2)
else
    e1:SetReset(RESET_PHASE+PHASE_DRAW+RESET_SELF_TURN)
end
Duel.RegisterEffect(e1,tp)

The reset is subtle. If the effect is activated during your own Draw Phase, the script uses a count of 2 so the current Draw Phase does not consume the skip immediately.

Common Restriction Codes

Effect code	Common use
EFFECT_CANNOT_DRAW	A player cannot draw by effect or outside allowed timing.
EFFECT_CANNOT_SUMMON	A player cannot Normal Summon.
EFFECT_CANNOT_MSET	A player cannot Set a monster.
EFFECT_CANNOT_SPECIAL_SUMMON	A player cannot Special Summon matching monsters.
EFFECT_CANNOT_ACTIVATE	A player cannot activate effects matching the value function.
EFFECT_CANNOT_BP	A player cannot enter the Battle Phase.
EFFECT_SKIP_DP	A player's Draw Phase is skipped.
EFFECT_CANNOT_TO_HAND	Cards matching the target callback cannot be added to the hand.
EFFECT_CANNOT_DISCARD_HAND	Cards cannot be discarded from the hand under matching reasons.

Check Constants for the local numeric values. The important scripting question is not the number; it is whether the restriction targets players, cards, or a specific attempted action.

Common Mistakes

Mistake	Better pattern
Using SetTargetRange(LOCATION_MZONE,0) on a player-target restriction.	With EFFECT_FLAG_PLAYER_TARGET, use 1,0, 0,1, or 1,1.
Registering an oath restriction on the card instead of the player.	Use Duel.RegisterEffect(e,tp) for temporary player locks.
Forgetting to check past activity before applying a "for the rest of this turn" lock.	Use Duel.GetActivityCount in the chk==0 branch where local scripts do.
Treating a restriction SetTarget as a Chain target.	Restriction targets are engine filters, not selected Chain targets.
Resetting a phase skip too early.	Follow local phase-skip reset patterns when the current phase might match the skipped phase.

Player restrictions are powerful because they change what the engine allows. Keep the affected player, duration, and attempted-action filter explicit.