More then half the questions I receive as a judge are regarding priority. Priority is perhaps the most complex aspect of Yu-Gi-Oh. It took me about 5 months to search for all the facts and completely understand it. I am psyched that I have this opportunity to deliver all the facts about priority in a section that can be read in several minutes so that no one has to search for the answers regarding priority questions as I did ever again. When Yu-Gi-Oh first came out the rules were fairly simple; If I summon Catapult Turtle and you destroy Catapult turtle with Trap Hole then I couldnâ€™t use Catapult Turtle effect because it wasnâ€™t on the field. This is not longer the case; the game has become more complex and intricate. Yu-Gi-Oh is at the stage where game mechanics are taking precedence over card rulings; this allows judges to make snap decisions instead of having to memorize the rulings for every single card. When Konami introduced Yu-Gi-Oh in Japan when someone had a question Konami answered itâ€¦ that was the end of the discussion. When Yu-Gi-Oh hit U.S. shores people asked â€œwhy?â€. Example: Why does The Shallow Grave require both players to have an eligible target in their respective graveyards when Spear Cretin does not? (this will be explained in the â€œtiming and activation eligibilityâ€ section). Example: When both players have a Sangan on the field and 3 Exodia Limbs and the head of Exodia in their hands and Dark Hole is activated and resolves, who wins? Example: Who special summons their monsters first by the effect of Cyber Jar? These are some of the first questions we asked Konami; when Konami answered us, most of us wanted a reason. Priority is a very loosely used term, so keep that in mind as I explain it to you. The most common misconception is that a monster can have priority, this misconception arose when people started saying â€œI will use Tribe-infecting Virusâ€™s priority and activate his effectâ€; this is absolutely, 100%, incorrect. Only the people dueling can have priority, no monster or card of any sort can have priority; it is you, the player, who has priority. Some people will say that the turn player always has priority; our understanding of priority has since expanded. â€œTurn playerâ€ is a term coined to define the person whose turn it is. The most common situation where questions of priority arise is when the turn player summons a monster and wishes to use its effect but the non-turn player would like to use Ring of Destruction/Trap Hole/etc. to destroy that monster before itâ€™s effect can be activated. The fact of the matter is that the turn player has priority to activate the effect of the monster they have summoned followed by passing priority to the non-turn player to chain to the effect of that monster. By â€œpassing priorityâ€ I mean giving the opportunity to activate something from one player to another; in this case the example mentioned in the previous sentence the turn player was passing priority to the non-turn player. Hereâ€™s what confused meâ€¦ if my opponent can activate Tribe-Infecting Virusâ€™s effectâ€¦ how can I chain trap hole to the effect of another monster instead of activating it in response to the summoning of a monster? The short answer is that you just can, Konami said so. The reason Konami said this is because, in this example, it would be the first opportunity the non-turn player would have to activate Trap Hole; this can be applied to many situations. The only monster that currently does not get to use itâ€™s effect immediately after being summoned is Breaker the Magical Warrior; you summon Breaker the Magical Warrior and use your priority to activate his effectâ€¦ what does that mean? Breaker, as do many monsters, has two effects. It would be best for me to explain this using an example chain to avoid confusion: Activation -Player A summons Breaker the Magical Warrior and immediately activates his effect of adding a counter -Player B responds by activating Trap Hole -Player A chooses not to activate anything in response to Trap Hole -Player B chooses not to activate anything in response to Trap Hole Resolution -Player Bâ€™s Trap Hole resolves and destroys Breaker the Magical Warrior -The effect of player Aâ€™s Breaker the Magical Warrior resolves without effect because breaker is no longer on the field thus there is nothing to add a counter to Priority does not apply only to monsters that have just summoned, it applies all cards on the turn playerâ€™s side of the field. Lets say I have a set Torrential Tribute, a Breaker the Magical Warrior with a counter, and a Cannon Soldier on my side of the field. My opponent has a set Torrential Tribute and Magic Drain and I a summon Sinister Serpent, my opponent has to wait until either A)say I am not using my priority, B)activate Torrential Tribute, C)until I use Breaker the Magical Warriorâ€™s effect, or C)until I use Cannon Soldierâ€™s effect. Priority can be applied to someone entering a new phase. I state Iâ€™m ending my standby phase and pass priority to my opponent, my opponent passes priority back to me by choosing to not activate anything, I then enter my main phase 1. When I enter my main phase 1 I have priority to activate a magic card, trap card, a monsterâ€™s effect, flip summon a monster, etc. before my opponent can activate anything. Hereâ€™s another interesting situation that happened to me in a tournament the other night. I summoned Exiled Force and my opponent decided he wanted to use Trap Hole on it. I told him I wanted to use my priority to use Exiledâ€™s effect before he could use Trap Hole on itâ€¦ the thing was that he canâ€™t activate trap hole on a monster that isnâ€™t there. Exiled Force is a cost effect, the cost for Exiled Forceâ€™s effect is tributing him (Exiled Force), and, as we all know, costs are paid at activation, not resolution. This means that by the time my I pass priority to my opponent my Exiled Force is in the graveyard, this means he canâ€™t activate Trap Hole because the monster that was just summoned is now in the graveyard. This brings me to my next point. My opponent assumed I wasnâ€™t going to use Exiled Forceâ€™s effect and he paid the price for his assumption by letting me know that his face down card was a Trap Hole. When your opponent summons a monster with an effect always ask your opponent if he/she would like to use his/her priority to use the effect of the monster that has just been summoned. If you do not ask your opponent then priority is assumed. Let me explain why this is important. Player a has A has 1300 life points, a face down Trap Hole, three defense position goat tokens, and a defense position Magical Scientist. Player B has a face up attack position Mataza the Zapper, a Tribe-Infecting Virus and two other cards in his hand. Player B is afraid that player Aâ€™s face down Trap Hole is a Magic Cylinder and wants to win this turn, so he decides heâ€™s going to summon his Tribe-Infecting Virus and discard both cards in his hand to destroyed all beast and spellcasters. Player B summons Tribe-Infecting Virus and before he can say anything Player A, without asking if player B would like to use his priority, activated Trap Hole. Player B didnâ€™t care what kind of monster he discarded to destroy first and was going to chose spellcasters. Now that Player A has activated Trap Hole player B says â€œwait, Iâ€™m going to use my priority to discard to destroy all beast typesâ€. Player Bâ€™s Tribe-Infecting Virus is sent to the graveyard and all of player Aâ€™s goat tokens are gone. Player B now enters his battle phase, attacks player Aâ€™s Magical Scientist with Mataza the Zapper and then attacks with Mataza the Zapper again wipeing out player Aâ€™s life points. If player A had waited to activate Trap Hole till after Player B discarded to destroy all spellcasters, player A would still have 1 goat token and 1300 life points instead of having lost the duel. There are other times when priority is passed back and fourth. Every time someone activates a card priority is passed to the person who did not activate that card. Priority is passed to the non-turn player when the turn player wants to end one of their phases. Priority is passed when an action is performed or when a chain fully resolves. Another issue that doesnâ€™t technically fall under the category of priority but does have relevance to who the turn player is would be simultaneous effects. When a D.D. Warrior Lady attacks a Wall of Illusion what happens? They canâ€™t activate at the same time, that just isnâ€™t possible. The answer is that the effect of the turn playerâ€™s D.D. Warrior Lady is the first link in the chain and the effect of the non-turn playerâ€™s wall of Illusion is chain link 2. They resolve in reverse order; Wall of Illusionâ€™s effect resolves first sending D.D. Warrior Lady back to the hand of the turn player, then D.D. Warrior Lady resolves allowing the turn player to remove Wall of Illusion from play. D.D. Warrior Lady isnâ€™t removed from play because it is no longer on the field. Another example would be the question regarding Exodia, Sangan, and Dark Hole mentioned in the second paragraph of this section. The person who activated Dark Hole would be the turn player because you can only activate Dark Hole if itâ€™s your own turn. Dark Hole would resolve and destroy both playerâ€™s Sangans. The two Sangans would be put into a chain immediately following the resolution of Dark Hole; the turn playerâ€™s Sangan would be chain link 1 and the non-turn playerâ€™s Sangan would be chain link 2. Resolution occurs in reverse order; the effect of the non-turn playerâ€™s Sangan resolves first allowing the non-turn player to search for the final piece of Exodia â€“ the duel is over, the non-turn player wins and the effect of the turn playerâ€™s Sangan never resolves. I would like to note that the ONLY time spell speed 1 effects can be chained to one another is in situations with simultaneous effects, such as the one in the above paragraph, occurs. You can apply the rules applied to these situations to other cards with simultaneous effects. Some of the cards that come to mind are Cyber Jar, Morphing Jar #2, Dragged into the Grave, The Shallow Grave, Spear Cretin, Etc.