Rainbow Vale — ruling 1

If control of Rainbow Vale has somehow changed before the “at end of turn” ability resolves, the player who activated the mana ability (not the current controller of Rainbow Vale) chooses one of their opponents to gain control of it.

Rainbow Vale — ruling 2

If Rainbow Vale’s ability is activated during an End step, its “at the beginning of the end step” trigger won’t trigger until the End step of the next turn. If its ability is activated again during that turn, its “at the beginning of the end step” ability will trigger twice at the End step of that turn.

Rainbow Vale — ruling 3

If more than one player manages to tap it for mana in a given turn, then two control-change abilities will trigger at end of the turn. These abilities resolve using the standard order for such things, so the active player’s triggers are put on the stack first, then the opponents’.

Rainbow Vale — ruling 4

The opponent is chosen when the “at end of turn” triggered ability resolves.

Rainbow Vale — ruling 5

Only changes controller at the end of a turn in which it was tapped for mana. It does not change controller if it is not tapped for mana.

Rainbow Vale — ruling 6

Stays in the same tapped/untapped state it is in when it switches controllers.

Rainbow Vale : règles, fonctionnement et interactions (MTG)

Rainbow Vale is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

: Add one mana of any color. An opponent gains control of this land at the beginning of the next end step.

How it works : Rainbow Vale

Original English text — Wizards of the Coast / Scryfall

#1September 16, 2007· Wizards of the Coast
If control of Rainbow Vale has somehow changed before the “at end of turn” ability resolves, the player who activated the mana ability (not the current controller of Rainbow Vale) chooses one of their opponents to gain control of it.
No other card is named in this ruling.
#2September 16, 2007· Wizards of the Coast
If Rainbow Vale’s ability is activated during an End step, its “at the beginning of the end step” trigger won’t trigger until the End step of the next turn. If its ability is activated again during that turn, its “at the beginning of the end step” ability will trigger twice at the End step of that turn.
No other card is named in this ruling.
#3September 16, 2007· Wizards of the Coast
If more than one player manages to tap it for mana in a given turn, then two control-change abilities will trigger at end of the turn. These abilities resolve using the standard order for such things, so the active player’s triggers are put on the stack first, then the opponents’.
No other card is named in this ruling.
#4September 16, 2007· Wizards of the Coast
The opponent is chosen when the “at end of turn” triggered ability resolves.
No other card is named in this ruling.
#5October 4, 2004· Wizards of the Coast
Only changes controller at the end of a turn in which it was tapped for mana. It does not change controller if it is not tapped for mana.
No other card is named in this ruling.
#6October 4, 2004· Wizards of the Coast
Stays in the same tapped/untapped state it is in when it switches controllers.
No other card is named in this ruling.