Effect
Each time a "Spellbook" Spell Card is activated, place 1 Spell Counter on this card. All Spellcaster-Type monsters you control gain 100 ATK for each Spell Counter on this card. When this card with Spell Counter(s) is destroyed and sent to the Graveyard: You can add 1 Spellcaster-Type monster from your Deck to your hand, whose Level is less than or equal to the number of Spell Counters that were on this card.
The effect "As long as this card remains face-up on the field, each time you or your opponent activates a 'Spellbook' Spell Card, place 1 Spell Counter on this card" is an effect that does not start a Chain.
This is applied when "Spellbook Library of the Crescent" itself is face-up in the Spell & Trap Zone and a "Spellbook" Spell Card is activated by you or your opponent, at which point a Spell Counter is placed. (It is not applied when the effect of a "Spellbook" Spell Card is activated.)
The effect "All Spellcaster-Type monsters you control gain 100 ATK for each Spell Counter on this card" is an effect that does not start a Chain.
The effect "When this card with a Spell Counter(s) is destroyed and sent to the Graveyard: You can add 1 Spellcaster-Type monster from your Deck to your hand whose Level is less than or equal to the number of Spell Counters that were on this card" is an effect that activates in the Graveyard and starts a Chain. (It does not target. It can also be activated during the Damage Step.)
Continue with related public research
From this rulings page you can jump back into card data, set archives, tournament decks, banlist checks, and market movers.
Card database
Search Yu-Gi-Oh! cards, archetypes, stats, and printings.
Set archive
Navigate booster sets and inspect all cards in each release.
Tournament decks
Browse competitive decklists, player finishes, and archetype trends.
Banlist status
Check the current status of Yu-Gi-Oh! cards on the banlist.
Market movers
Track the top Yu-Gi-Oh! price gainers and momentum cards.