King Monster Zones

King Monster Zones (Japanese: キングモンスターゾーン Kingu Monsutā Zōn, abbreviated モンスターゾーン in card text) are being treated as "King Monster Zones" by King Cards in which monsters Summoned from the  can be placed. These Monster Zones are introduced by Master Rule ROYAL, which will come into effect with the release of Kingship of the Duelist.

Any monster Special Summoned from the Extra Deck can be Summoned to a King Monster Zone. (See King Summoning)

Unlocking King Monster Zones
By activating a King Card, select any number of empty Main Monster Zones depending of that card's King Hierarchy, these Monster Zones are then treated as "King Monster Zones" where monsters can be summoned from the Extra Deck. This action is treated as "Unlocking" (Japanese: Kai jō) King Monster Zones.

Rulings

 * King Monster Zones can only be unlocked by King cards
 * A King card's King Hierarchy determines the number of Unlockable King Monster Zones (You can choose those zones.)
 * Before using it to unlock a King Monster Zone, the Main Monster Zone(s) must be empty. Monster Zones that are occupied cannot be used.
 * When a monster Special Summoned from the Extra Deck leaves a King Monster Zone (by being destroyed, banished, or sent back to the Extra Deck/hand), that zone reverts to a Main Monster Zone; however, you can still re-unlock that same King Monster Zone during your turn with another King Card.
 * King cards can continue to unlock King Monster Zones up to their King Hierarchy during each of your turns while they are face-up in your field if they are treated as Continuous or Field cards by their Spell Indicators.
 * King Cards cannot unlock the same King Monster Zones that they previously unlocked, even if that same King Monster Zone has been reverted to a Main Monster Zone. If Continuous or Field King Cards haven't used up all of their King Hierarchy during that same turn, they must unlock other Zones that haven't been unlocked yet with that same card.
 * A King Monster Zone is still treated as such even if a Link Monster's Link Arrows are pointing there.
 * The 2 Extra Monster Zones cannot be used to Unlock King Monsters Zones.
 * You can Special Summon monsters from the Extra Deck to Monster Zones that a Link Monster's Link Arrows point to if it is Summoned to a King Monster Zone.
 * Even if a King card leaves the Field, a King Monster Zone(s) remains unlocked for the remainder of the turn, unless it is reverted to a Main Monster Zone by card effects.
 * During each player's End Phase, empty King Monster Zones are reverted to Main Monster Zones.

Card Text
The term "Unlocking" (Japanese: Kai jō) must be used in card's text when describing the act of treating a number of Main Monster Zones as King Monsters Zones upon the activation of a King Card.

For example, instead of "Once per turn, if this card treats up 2 Main Monster Zones as King Monster Zones: Special Summon 1 Extra Deck monster from your GY to 1 King Monster Zone", it should be "Once per turn, if this card Unlocks up to 2 King Monster Zones: Special Summon 1 Extra Deck monster from your GY to 1 King Monster Zone".

This is done in order to avoid excess of.