Only One "Special Summon Itself From the Hand" Trigger Effect Per Chain

A player may activate at most one Trigger Effect that could Special Summon the monster itself from the hand on a given Chain — even when several different monsters have their trigger condition met by the same event. This is the rule informally called the "Green Baboon" rule.

Official rule: Each player can only activate 1 Trigger Effect of a monster that could Special Summon the monster itself from the hand per Chain.

The cap counts the effect's capability, not where the copy currently is. If the effect text can Special Summon the monster from the hand — even via an "or hand" clause, and even if the specific copy is in the Graveyard — it counts against the one-per-chain limit.

Worked example — Ponix + Sacred Fire King Garunix

Relevant card text

Legendary Fire King Ponix

"If your monster(s) that was originally FIRE is destroyed by battle or card effect: You can Special Summon this card from your hand. …"

Sacred Fire King Garunix

"If your monster(s) that was originally FIRE is destroyed by battle or card effect: You can Special Summon this card from your GY (if it was there when the monster was destroyed) or hand (even if not). …"

The play

Your opponent uses Fire King Island to destroy their own Legendary Fire King Ponix on the field (and search a Fire King High Avatar Kirin). That destruction meets the trigger condition of both Sacred Fire King Garunix in the GY and a second Legendary Fire King Ponix in the hand. They want to put both on the same chain — Sacred Fire King Garunix as Chain Link 1, Legendary Fire King Ponix as Chain Link 2 — to Special Summon both.

Correct ruling

No — only one of them may be activated on this chain. Both are Trigger Effects that could Special Summon the monster from the hand: Legendary Fire King Ponix summons itself from the hand, and Sacred Fire King Garunix's effect can summon itself "from your GY … or hand." Because Sacred Fire King Garunix's effect is capable of a hand Special Summon, it counts under the cap even though this copy is in the GY. The player picks one to activate; the other cannot be added to the same chain.

The tempting wrong answer — "they're separate cards with the same trigger, so stack both as CL1 + CL2" — ignores the per-chain cap specific to self-Special-Summon-from-hand triggers. The contention "one or the other, but not both in the same chain" is correct.

Why the rule exists, and its scope

The restriction stops a single event from flooding one chain with multiple hand Special Summons (historically Gorz the Emissary of Darkness / Battle Fader / Tragoedia / Green Baboon, Defender of the Forest style cards). Scope notes:

• It is one per Chain, per player — you may still activate one such effect on a later chain.
• It only caps self-Special-Summon-from-hand Trigger Effects. Other Trigger Effects triggered by the same event (searches, destructions, non-hand summons) are unaffected and follow normal SEGOC ordering.
• It keys on "could … from the hand." An effect that can only Special Summon from the GY/Deck (no hand option) does not fall under this cap.

Judge calls to watch for

• Two monsters with the same destruction trigger that each could Special Summon themselves from the hand → only one goes on the chain. Do not place both as CL1 + CL2.
• The cap follows the effect text's capability, not the copy's current zone: an "or hand" summon effect counts even when activated from the GY.
• Do not extend the cap to non-hand self-summons or to unrelated triggers from the same event.
• See SEGOC for how the one chosen effect is ordered with other simultaneous triggers, and Summoning conditions are not effects.

Sources

• Official Yu-Gi-Oh! TCG rule "Each player can only activate 1 Trigger Effect of a monster that could Special Summon the monster itself from the hand per Chain" — Yugipedia "Simultaneous Effects Go on a Chain"
• Yugipedia/Fandom "Card Rulings:Green Baboon, Defender of the Forest". Card text (Legendary Fire King Ponix, Sacred Fire King Garunix) via YGOPRODeck API. Community confirmation: the "Green Baboon" rule blocks Ponix + Garunix on the same chain even with Garunix in the GY, because Garunix's effect can Special Summon from the hand.
• db.ygoresources.com Q&A 24340 (2026-06-05): official confirmation that the cap is hand-capability-scoped — Trigger Effects that can only activate from the Graveyard (and cannot Special Summon the monster from the hand) are exempt, so several such GY-only self-Special-Summon triggers (e.g. Royal Archfiend, Duke Archfiend) can all activate on the same Chain. https://db.ygoresources.com/data/qa/24340