Expert Gameplay FAQ: Infinite Loop

An infinite loop is a never-ending cycle of cards trying to resolve.
Because of this, a ruling was introduced that states you may not activate a card knowing that it will cause an infinite loop with No Net Change.

EXAMPLE #1: Player 1 has "Pole Position", "Luminous Spark" (+500 to LIGHT), and "Gemini Elf" (1900 ATK / EARTH) face-up on the field. "Gemini Elf" is the monster on the field with the highest ATK, so it is unaffected by Spell Cards. If a Player Summons "X-Head Cannon" (1800 ATK / LIGHT), "Luminous Spark" will raise the ATK of "X-Head Cannon" to 2300, making it the highest ATK monster on the field, so it's unaffected by Spell Cards due to "Pole Position", so it drops to 1800 ATK, then increases to 2300, then drops to 1800, etc. This would create an infinite loop. Therefore, neither Player can Summon "X-Head Cannon". (Taken and edited slightly from "Pole Position's" ruling page).
See Pole Position's rulings for other examples of infinite loops with No Net Change.

EXAMPLE #2: Player 1 used a card like "Snatch Steal" to take control of one of Player 2's monsters. Afterward, if Player 2 summons "Cyber Blader" while Player 1 has three monsters (including the monster equipped with "Snatch Steal"), the effect of "Cyber Blader" negates "Snatch Steal" thus returning the stolen monster to Player 2. This reduces the monsters on Player 1's side of the field and changes "Cyber Blader's" effect into doubling it's own attack. As "Snatch Steal" is no longer negated, the equipped monster will return to Player 1 starting the process over again creating an infinite loop.
If the conditions are right (three monsters are on the opponent's field when "Cyber Blader" would be Summoned), then "Cyber Blader" cannot be Summoned. If "Cyber Blader" was already active, then "Snatch Steal" cannot be activated.

If the infinite loop would not be activated by a Player but instead by an uncontrollable means, the causing card is destroyed.

If Player 1 has "Jam Breeding Machine" active, a monster stolen by the opponent by "Snatch Steal" and another monster, the opponent CAN Summon "Cyber Blader". In the case where the Player (Player 2) ends their turn and the turn of Player 1 has them Draw and go into Standby Phase where a Token would be created causing the Loop, the trigger card would be destroyed by game mechanics. This could be "Cyber Blader", "Snatch Steal", or "Jam Breeding Machine". It would require a judge to determine the causing card but would most likely be "Jam Breeding Machine" due to that card's effect summoning the Token.

Net Change is when a Loop is activated that has a change occur for certain. After the Loop is active it will continue until it stops producing a change and then the card causing it will be destroyed by Game Mechanics.

EXAMPLE with Net Change #1: The cards "Morphing Jar #2", "All-Out Attacks", and "Hiro's Shadow Scout" are face-down on your field. Activating "All-Out Attacks" will flip both your monsters face-up causing both effects to activate and recycle. See the All-Out Attacks OTK page for full details. Some other ideas are listed. When the loop is unable to continue, the faulting card is destroyed by Game Mechanics. In this example, the destroyed card would be "All-Out Attacks".

When the Loop is controlled by a player, the Loop can be stopped at any time by that player. As such, a Controlled Loop is legal for use.

EXAMPLE #1 of a "Controlled Loop": The Quillbolt Loop. This uses "Quillbolt Hedgehog's" ability to Special Summon itself by having a Tuner on the field and follows by having a "tribute for damage" card on the field. Using "Imperial Iron Wall" prevents "Quillbolt Hedgehog" from being removed from play.

EXAMPLE #2 of a "Controlled Loop": The Flint Equip Loop. This uses "Flint" and two "Flint Locks" to pass the "Flint" back and forth. The Spell Card "Morale Boost" is used to gain 1000 Life Points every time an Equip Card is equipped. Because no Equip card leaves the field, the 1000 Life Point loss is never reached. This allows a player to gain infinite Life Points while the opponent may be powerless to stop it. Combined with "Fire Princess", this creates an OTK.

EXAMPLE #3 of a "Controlled Loop": Using "Butterfly Dagger - Elma" (Traditional Only) and "Gearfried the Iron Knight". Each time "Butterfly Dagger - Elma" is equiped to "Gearfried the Iron Knight" it is destroyed by "Gearfried the Iron Knight's" effect and sent to the graveyard.

One has the player user a Face-up "Royal Magical Library" to draw cards from the deck. Since a Spell Card was activated "Royal Magical Library" gains a Spell Counter. "Butterfly Dagger - Elma" is returned to the hand and the loop is repeated. When "Royal Magical Library" has three spell counters you draw a card. Repeat.

Another option uses "Spell Absorption". This allows you to gain 500 Life Points whenever a Spell Card is activated. This allows you to have neigh infinite Life Points and can be changed to a OTK with a card such as "Fire Princess".

EXAMPLE #4 of a "Controlled Loop": See Elemental HERO Gustav Max OTK