REDU format ruling
The Shallow Grave

Nearest-era rulings (Tengu, Sept 2011) — no REDU-specific archive exists.
Card effect (current official text)Each player targets 1 monster in their own GY; each player Special Summons the target from their GY in face-down Defense Position.
Rulings
- If The Shallow Grave is activated while Light of Intervention is active, the monsters are Special Summoned in face-up Defense Position.
- The Shallow Grave cannot be activated if either play has no open Monster Card Zones or if either player does not have a monster in their GY that they can Special Summon.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the REDU forum — sourced change requests get reviewed.