Card Rulings:Formula Synchron

TCG Rulings
your opponent wants to end Main Phase 1 does not force them to continue into their Battle Phase. Summon. monsters are available to you. If you cannot, your opponent can verify that you have no monsters in your Extra Deck that can be Summoned.
 * The effect to draw 1 card starts a Chain.
 * The effect to Synchro Summon during your opponent’s Main Phase is a Quick Effect.
 * You cannot activate the effect to Synchro Summon multiple times in the same Chain.
 * You can activate the effect to Synchro Summon during your opponent’s Main Phase 1 or 2. Using it when
 * You send the Synchro Material Monsters to the Graveyard when you resolve the effect to Synchro
 * You must Synchro Summon when the effect resolves, if possible, using Formula Synchron and the faceup