Ignition Effect
Ignition Monster Effects (起動効果, Kidōkōka) are Spell Speed 1 effects that require a manual activation by the card's controller during their own Main Phase 1 or 2 (except "Red-Eyes Wyvern", "Daigusto Eguls", "Alchemic Magician", "Speed Warrior", "Splendid Rose", "General Gantala of the Ice Barrier", "Justice of Prophecy", and "Number 107: Galaxy-Eyes Tachyon Dragon"). This type of effect used to be called a Cost Effect in the early days of Yu-Gi-Oh!, which was slightly confusing because not all of those monsters had a cost.
Examples of monsters with Ignition Effects: "Cyber Gymnast", "XYZ-Dragon Cannon", "Bazoo the Soul-Eater", "Blackwing - Gale the Whirlwind", "3-Hump Lacooda", "Card Trooper", "Dark Simorgh", "Lonefire Blossom", "XX-Saber Faultroll" and most Xyz Monsters.
Priority
Previously, the turn player had priority to activate Ignition Effects before an opponent could activate a fast effect. This was removed from the OCG on March 19, 2011, and from the TCG on April 25, 2012.
For example, before the abandonment of Ignition Effect priority, the turn player could Summon "Lonefire Blossom" and activate its effect before their opponent could activate "Eatgaboon".
Since the abandonment of Ignition Effect priority, Ignition Effects cannot be activated in the Summon response window, requiring an open game state.
Example
