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

The rule says: Delivering a double-check is worth +5, and triple-checks are worth +15 Is a double check when I am checking two players at one move checking one player with a normal double check

List of chess variants - Wikipedia

Updates to 4 Player Chess - Chess Forums

Double Check - Chess Terms

Four-Way Chess – Green Chess

CHESS BOARD SET: A twist on the classic game of chess for 2-4 players. This chess set is great for more advanced seasoned players who are up for a

WE Games Four Player Chess Set, Chess Board for Team Chess, Combination Chess Game for Up to 4 Players, Unique Chess Sets for Adults and Kids, Roll Up

Forcing the King to run with the Double Check, Chess Tactics

How I Finally Got to 2000 ELO on Chess.com, by Shachar pan, Getting Into Chess

What does the †† notation mean? - Chess Stack Exchange

7 Tips to Cure Chess Blunders - TheChessWorld