Chess18 is the subset of Chess960 in which the kings and rooks are fixed, so that castling is always orthodox, preserving more of the feel of ordinary chess. This allows some opening knowledge to still have practical relevance – one could practically learn a few short lines for each of the eighteen starting positions – though it does not reach the extent of orthodox chess, in which one has to memorize many long computer lines. Moreover, this excludes all starting positions where White has a large advantage, and makes early blunders less common by making it impossible for a bishop to attack an undefended pawn after White's first move.Weeks, Mark. "Chess324 Is a Thing", 2022-09-05.Kaufman, Larry. "Chess324", 2022-08-12.Stefan Pohl, Anti Draw Openings However, due to having fewer starting positions and the requirement that the king and rooks must start on traditional starting squares, Chess18 has much less positional diversity than is offered by Chess960. Additionally, while memorizing openings is more difficult in Chess18 than in traditional chess, opening preparation has the potential to be a much more significant aspect of the game than in Chess960, especially for grandmasters and top players. Chess18 positions are more likely than Chess960 positions to resemble structures found in traditional chess due to the limited starting positions in Chess18 in comparison to the diversity of starting positions found in Chess960.
Chess18 is the subset of Chess960 in which the kings and rooks are fixed, so that castling is always o.rthodox, preserving more of the feel of ordinary chess. This allows some opening knowledge to still have practical relevance – one could practically learn a few short lines for each of the eighteen starting positions – though it does not reach the extent of orthodox chess, in which one has to memorize many long computer lines. Moreover, this excludes all starting positions where White has a large advantage, and makes early blunders less common by making it impossible for a bishop to attack an undefended pawn after White's first move.Weeks, Mark. "Chess324 Is a Thing", 2022-09-05.Kaufman, Larry. "Chess324", 2022-08-12.Stefan Pohl, Anti Draw Openings However, due to having fewer s!tarting positions and the requirement that the king and rooks must start on traditional starting squares, Chess18 has much less positional diversity than is offered by Chess960. Additionally, while memorizing openings is more difficult in Chess18 than in traditional chess, opening preparation has the potential to be a much more significant aspect of the game t:han in Chess960, especially for grandmasters and top players. Chess18 positions are more likely than Chess960 positions to resemble structures found in traditional chess due to the limited starting positions in Chess:18 in comparison to the diversity of starting positions found in Chess960.