When a monster is Successfully Summoned, the turn player is able to activate an Ignition Effect before the opponent can respond.
When a chain has finished resolving, the turn player is able to activate an Ignition Effect before the opponent can respond.
An Ignition effect is any effect that can only be activated in your Main Phase. For example, the effect of "Exiled Force" is an Ignition effect.
Example 1 - Basic Example
● If “Black Luster Soldier - Envoy” is Summoned, its effect can be activated,
before the opponent can activate “Jar of Greed”.
● Then, "Jar of Greed" can be activated as Chain Link 2.