Why the extra rank on each side in 4 player chess? - Chess Stack Exchange

Why do we have an extra rank (marked with the red lines) on each side in 4 player chess? What could be the possible logic? (screenshot is taken from chess.com)

Couldn't Be More Convenient to Take Along: With a proper size,that's, 12x 6 x 1.8, of the foldable chess board, the chess set is easy to take along

AMEROUS 12 x 12 Magnetic Wooden Chess Set for Kids and 6 up Age, 2 Bonus Extra Queens, Folding Board with Storage Slots, Handmade Chess Pieces

Introducing Elon Musk Chess: Chess with a 14x14 grid, fog of war, a tech tree, a randomized map, 4 players, and different pieces for each side! : r/AnarchyChess

algorithm - Which Data Structure is Best to represent a Three-Player Chess Board? - Stack Overflow

How many blunders does an above advanced chess player make? - Quora

4 Player Chess - Chess Forums

Chess Game For Beginners: Learn the rules and master the moves of beginner chess in no time with a step-by-step instructive guide! This chess learning

Chess Set for Kids and Adults | Beginners Chess Game with Step-by-Step Teaching Guide | Learning Chess Board Game for Boys and Girls Chess for Kids

4 Player Chess - Chess Terms

analysis - Why is Be6 a better move than Bh5 in this position? - Chess Stack Exchange

matrices - Can a dominance matrix be used for ranking? - Mathematics Stack Exchange

BACKGAMMON + CHESS LARGE - Logica Puzzles

Everbody knows back-rank checkmate but what about the side-rank checkmate? :) - Chess Forums