Tectonic Edge — ruling 1

Tectonic Edge’s second ability checks how many lands an opponent controls only at the time you activate the ability.

Tectonic Edge — ruling 2

Assuming you can activate Tectonic Edge’s second ability, you can target any nonbasic land with it (not just one controlled by an opponent that controls four or more lands).

Tectonic Edge : règles, fonctionnement et interactions (MTG)

Tectonic Edge 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 . , , Sacrifice this land: Destroy target nonbasic land. Activate only if an opponent controls four or more lands.

How it works : Tectonic Edge

Original English text — Wizards of the Coast / Scryfall

#1March 1, 2010· Wizards of the Coast
Tectonic Edge’s second ability checks how many lands an opponent controls only at the time you activate the ability.
No other card is named in this ruling.
#2March 1, 2010· Wizards of the Coast
Assuming you can activate Tectonic Edge’s second ability, you can target any nonbasic land with it (not just one controlled by an opponent that controls four or more lands).
No other card is named in this ruling.