Ever seen one of these boards? Four kings, four queens, six rooks

rules - Escaping a double check - Chess Stack Exchange

an interesting double check mate! : r/chessbeginners

John with a Double Check Checkmate!

My first ever double check checkmate : r/chessbeginners

What does double-check mean in four-player chess on chess.com

Chess 101: What Is Double Attack? Learn About the Different Types

Apparently, someone thinks a discovered double check winning a pawn and a rook ain't the best move (Please help) : r/ChessPuzzles

Double Check - Learn to Play Chess

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Master Chess Strategy: Avoid Mistakes and Win with Double Check