Ritual Summon Choices

Before this lesson: read Ritual Procedures. Goal: understand monster selection, legal material groups, backing out to choose again, and optional effects around a Ritual Summon.

These are the standard helpers in Utilities/procedure.lua. The Rush Ritual helper has a different interface and data convention.

Start With A Complete, Small Spell

This tutorial Ritual Spell summons one Ritual Monster from the hand using materials whose Ritual Levels exactly equal that monster's original Level. Create a matching database entry with TYPE_SPELL+TYPE_RITUAL and a script with that card's ID.

local s,id=GetID()

function s.initial_effect(c)
    aux.AddRitualProcEqual(c)
end

The omitted filter allows any Ritual Monster that aux.AddRitualProcEqual finds legal. It does not bypass that monster's summon or material restrictions. For a named family, pass a filter: Super Soldier Ritual (14094090) uses aux.AddRitualProcEqual(c,c14094090.ritual_filter) and restricts the candidate Ritual Monsters to set 0x10cf.

Test the tutorial with two Ritual Monsters in hand. Only monsters for which a legal material set and summon destination exist should be offered. Choosing one of them then determines the material-selection rules.

Follow The Choice Loop

RitualUltimateTarget checks whether a summon exists at activation. It does not commit a particular Ritual Monster or material set. At resolution, RitualUltimateOperation follows this loop:

1. Rebuild the material pool and the eligible Ritual Monster choices.
2. Ask the player to choose one Ritual Monster.
3. Filter the materials for that exact monster, excluding the monster itself.
4. Ask the player to choose a valid material subgroup.
5. If that selection returns nil, go back to step 1.
6. Otherwise, record and move the materials, then summon the chosen monster.

The actual material-selection block is:

-- Bounded excerpt from RitualUltimateOperation:
-- mg is filtered for tc; lv is the selected monster's requirement.
Auxiliary.GCheckAdditional=Auxiliary.RitualCheckAdditional(tc,lv,greater_or_equal)
mat=mg:SelectSubGroup(tp,Auxiliary.RitualCheck,true,1,lv,tp,tc,lv,greater_or_equal)
Auxiliary.GCheckAdditional=nil

The next statement in the source is if not mat then goto RitualUltimateSelectStart end. That label is before the material-pool and monster-selection steps. The helper clears the temporary group hook before going back.

Back means “choose again”

The true argument enables cancellation of this material selection. The surrounding code decides what cancellation means. Here it returns to monster choice without paying or releasing anything. Changing the goto to return would let the player abandon the resolving Ritual effect instead.

Compare Sonic Tracker (17888577): its manual operation uses the same backtracking pattern, then stores the selected materials' total Level before releasing them. This is why a manual procedure must preserve more than just the final SpecialSummon call.

A Legal Material Set Is More Than A Total

aux.RitualCheck checks the destination's space after the chosen materials leave, the required total, the Ritual Monster's mat_group_check, and any active aux.RCheckAdditional hook. A full field is not automatically illegal if releasing a selected monster makes room.

The helper also filters ordinary materials with Card.IsCanBeRitualMaterial(candidate,chosenMonster) and applies the chosen monster's mat_filter when it has one. A candidate may be valid for Ritual Monster A and invalid for Ritual Monster B.

With ordinary Level values and no other restrictions, the distinction between the two common modes looks like this:

Requirement	Selected material Levels	Total check
Exactly 8	4 + 4	Can satisfy the exact total.
Exactly 8	4 + 5	Cannot satisfy the exact total.
8 or more	4 + 5	Can satisfy the required total.
8 or more	8 + 1	The extra material is unnecessary; preserve the helper's material-selection restrictions.

Do not replace the material predicate with g:GetSum(Card.GetLevel)>=lv. Materials use Card.GetRitualLevel(material,ritualMonster), which can encode alternative values. Zone availability and card-specific restrictions also remain part of the answer.

The ordinary helper compares against the Ritual Monster's original Level; the 2 variants use its current Level. That choice changes the required total, not the fact that materials use GetRitualLevel.

Three Independent Filters

Here is the first-effect registration from Revendread Origin (94666032), renamed to s and bounded to its Ritual effect. Its separate GY protection effect is omitted.

local s,id=GetID()

function s.initial_effect(c)
    aux.AddCodeList(c,4388680)
    aux.AddRitualProcGreater2(c,s.ritualFilter,
        LOCATION_HAND+LOCATION_GRAVE,s.graveMaterialFilter)
end

function s.ritualFilter(c)
    return c:IsSetCard(0x106)
end

function s.graveMaterialFilter(c)
    return c:IsRace(RACE_ZOMBIE)
end

Read the arguments separately:

Argument	Question
s.ritualFilter	Which Ritual Monsters may be summoned?
LOCATION_HAND+LOCATION_GRAVE	Where may the Ritual Monster be selected from?
s.graveMaterialFilter	Which extra GY monsters may be considered as materials?
The next optional mat_filter argument	How should the ordinary material pool be restricted?

Allowing the Ritual Monster to come from the GY does not automatically allow GY materials. Supplying GY material does not automatically allow the Ritual Monster to be summoned from the GY. The helper's extra-GY path checks Level, Monster type, and ability to banish; ReleaseRitualMaterial handles that material route. Do not replace it with ordinary Duel.Release.

For an unusual source of the summoned monster, Stars Align Above the Shrine (15306543) uses LOCATION_DECK in paired RitualUltimateTarget/RitualUltimateOperation factories, with a separate field-material filter. Its other effects and restrictions still matter.

For unusual material, Nekroz Kaleidoscope (51124303) can select an Extra Deck monster and send it to the GY rather than release it. It can also summon a Group of Ritual Monsters. That manual procedure is not reproduced by changing only summon_location on a one-monster helper.

Choosing A Mode At Activation

Mitsurugi Magatama (76725398) lets the player choose between a destruction route and a Ritual route. Its target callback calculates whether each route is currently legal, then presents only the available modes.

This is the bounded option-selection fragment, after b1 and b2 have been computed from the card's complete legality checks:

local op=aux.SelectFromOptions(tp,
    {b1,aux.Stringid(id,1),1},
    {b2,aux.Stringid(id,2),2}
)

aux.SelectFromOptions uses the final entry in each option as its stable returned value. If only the Ritual choice remains, its result is still 2; it does not become mode 1 because it is the first visible row. The real script stores the chosen mode in e:SetLabel, adjusts categories and targeting properties for that route, and resolves the matching branch later.

The Ritual branch invokes the helper factory, then its returned callback:

-- Bounded excerpt inside the selected Ritual resolution branch:
aux.RitualUltimateOperation(s.ritual_filter,Card.GetLevel,"Greater",
    LOCATION_HAND,nil,s.mfilter)(e,tp,eg,ep,ev,re,r,rp)

Do not choose a different mode at resolution just because its materials now look better. Recheck the chosen mode's resources instead. The selected mode is a decision made at activation; its Ritual Monster and materials are later decisions made by that branch.

Optional Follow-Up Work And Callback Limits

Recette de Viande (14166715) supplies an extra_operation callback to offer its position-changing follow-up. Its first guard is if not tc or not tc:IsCode(53618197) then return end, and it checks for applicable opposing monsters before asking SelectYesNo.

In the local helper, extra_operation runs after the main operation block even if no Ritual Monster was selected. Treat tc and mat as possibly missing. The callback being invoked is not a Boolean success report from Duel.SpecialSummon; if bespoke behavior needs that exact result, preserve the summon-result check in a suitable manual operation.

Two related settings are easy to misread:

• pause=true delays registration of the effect so the script can adjust it, as Mitsurugi Mirror (49721684) does before adding a count limit. It does not pause gameplay or enable cancellation.
• extra_target runs after the helper's chk==0 branch has already returned. Use it for activation-time announcements or bookkeeping. It cannot add a missing activation-legality test to that branch.

Recheck At Resolution

The helper recollects both ordinary and extra GY materials on each pass through the choice loop. If the intended monster or its resources disappear before resolution, the current candidate search decides what remains legal. Avoid storing an activation-time material Group and treating it as a confirmed selection.

For manual extensions, keep target and operation filters consistent, clean up temporary aux.GCheckAdditional hooks on every path, and move materials only after the player confirms a legal set. Read the chosen materials' values before moving them if the later effect needs their former state.

Practice And Review

Test state	Expected behavior to verify
Two Ritual Monsters are legal	Choose either; material legality follows that chosen monster.
Cancel material selection	Return to monster choice without releasing cards.
Full field with a legal field material	The checker can account for the zone freed by that material.
Only a GY Ritual Monster is allowed	summon_location enables it; this alone grants no GY material access.
A material is removed before resolution	The old material pool is discarded and legality is rebuilt.
Only option 2 is legal	Its stable returned value remains 2.
Follow-up is optional or has no candidate	Declining it or lacking candidates does not undo the Ritual Summon.
No Ritual Monster survives the resolution check	The follow-up callback handles missing tc without an error.

Continue with Fusion Summon Choices to compare this backtracking flow with separate normal/Chain Material routes.

Source Trail

• Utilities/procedure.lua: RitualUltimateTarget, RitualUltimateFilter, RitualUltimateOperation, RitualCheck, RitualCheckAdditional.
• Utilities/utility.lua: SelectFromOptions.
• Scripts/c17888577.lua: manual backtracking and material-value capture.
• Scripts/c94666032.lua, c15306543.lua, c51124303.lua: distinct monster sources, GY material, and Extra Deck material.
• Scripts/c76725398.lua, c14166715.lua, c49721684.lua: mode choice, optional follow-up, and deferred registration.