Author's Note:
For the second line reference of Amano-Iwato, I decided NOT to alter the line to summarize the basic information.
I felt as if citing the whole thing verbatim was unnecessary in that case, seeing that it's text summarizes it quite clearly.
Source: https://www.db.yugioh-card.com/yugiohdb/faq_search.action?ope=4&cid=13252&request_locale=ja
Card Text:
Cannot be Special Summoned.
①: Monsters cannot activate their effects, except Spirit monsters.
②: Once per turn, during the End Phase, if this card was Normal Summoned or flipped face-up this turn: Return this card to the hand.
①: The monster effect, "Monsters cannot activate their effects, except Spirit monsters." is a Continuous Effect.
②: The monster effect, "Once per turn, during the End Phase, if this card was Normal Summoned or flipped face-up this turn: Return this card to the hand." is a Trigger Effect. (It does not target.)
■ When resolving the monster effect, "Return this card to the hand.", if "Amano-Iwato" is in face-down Defense Position by the effect of "Book of Moon" OR destroyed by a card effect and sent to the Graveyard etc., the effect will NOT activate in the End Phase.
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Question:
While the effect of Ama-no-Iwato is applying, can I activate monster effects from the hand or Graveyard?
Answer:
The effect of Ama-no-Iwato prevents all monsters other than Spirit monsters from activating their effects. In addition to monsters on the field, this includes monsters in the hand or Graveyard that are not Spirit monsters.
Source: https://www.db.yugioh-card.com/yugiohdb/faq_search.action?ope=5&fid=21231&keyword=&tag=-1
Translated: https://ygorganization.com/ocg-circuit-break-rulings/
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Question:
While the effect of Ama-no-Iwato is applying, can the effect of Master Peace, the True Dracoslaying King be activated if it was Tribute Summoned by Tributing monsters?
Answer:
In this scenario, since Master Peace, the True Dracoslaying King is unaffected by monster effects, its effect that destroys a card on the field can be activated even while the effect of Ama-no-Iwato is applying.
Source: https://www.db.yugioh-card.com/yugiohdb/faq_search.action?ope=5&fid=21258&keyword=&tag=-1
Translated: https://ygorganization.com/ocg-circuit-break-rulings/