Edison format ruling
Card Guard

Card effect (current official text)If this card is Normal or Special Summoned: Place 1 Guard Counter on it. This card gains 300 ATK for each Guard Counter on it. Once per turn: You can target 1 other face-up card you control; remove 1 Guard Counter from this card, and if you do, place 1 Guard Counter on that target (if that card would ever be destroyed, remove 1 Guard Counter from it instead).
Rulings
(1) When this card is Normal or Special Summoned, place 1 Guard Counter on it. (2) This card gains 300 ATK for each Guard Counter it has. (3) Once per turn, you can remove 1 Guard Counter from this card and place it on 1 other face-up card you control. (C) If that card would be destroyed, remove the Guard Counter instead.
- The (1) mandatory Trigger Effect will only place a Guard Counter on it if is still face-up.
- The (2) Continuous Effect only affects itself while it has a Guard Counter on it.
- A different Monster with a Guard Counter on it does not gains 300 ATK.
- The (3) Ignition Effect MOVES the Guard Counter when the effect resolves.
- There is no cost associate with this effect.
- Moving the Guard Counter causes the (C) Condition to apply.
- The (C) Condition does not activate.
- It does not prevent cards from being destroyed by unpaid maintenance costs (ex: Mirror Wall).
- It does not prevent cards from destorying themselves by Continuous / Continuous-like Effects (ex: Giant Kozaky, Different Dimension Capsule, Call of the Haunted).
- This Condition applies even if Card Guard leaves the field.
- Guard Counters disappear if the monster is flipped face-down / leaves the field.
- This Conditino does not apply while Card Guard is holding the Guard Counter it generated.
- Two Card Guards can use their effects to switch Guard Counters such that they gain the protective Condition.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Edison forum — sourced change requests get reviewed.