This is an unofficial term for the activation timing of cards that response to the summon of a monster, such as "Bottomless Trap Hole", "Trap Hole", etc

This timing is after the "Summon negation window".

Cards like "Solemn Warning", "Solemn Judgment", etc that negate the summon of a monster cannot be activated during this window. They can only be activated in the "Summon negation window"

ExampleEdit

Player A declares he is going to summon "Black Luster Soldier - Envoy of the Beginning", the "Summon negation window" is opened and player B decides not to do anything (for example using cards like "Solemn Warning"), so the "Summon negation window" is closed

Now the "Summon response window" (or timing) is opened, and player B has the chance to active cards that respond to the Summon of a monster, such as "Bottomless Trap Hole", etc.

If player B chooses to active one of such cards, "Black Luster Soldier - Envoy of the Beginning" will be destroyed (or anything else depends on the card he used)

Note that even though "Black Luster Soldier - Envoy of the Beginning" is destroyed, its Summon was not negated, and it was considered to have been "successfully Summoned".

If player B passes without playing any such cards, nothing will happen to "Black Luster Soldier - Envoy of the Beginning", and the "Summon response window" is closed.

There is only one chain in the "Summon response window". After that, no card that response to the summon of a monster, such as "Trap Hole", can be activated.

Note that if the monster's Summon was negated in the "Summon negation window", there will not be any "Summon response window" followed.

Also note that in the "Summon response window", the turn player can claim his priority and active cards that response to the summon of a monster, such as "Trap Hole", to destroy his own monster, though this is almost never seen in normal play.