*Round: Round Boards are preferred for the consistent feel and distance from rail to shooting line. The downside of round rails is the difficult in manufacturing
Square & Octagonal: Square and Octagonal boards are consider easier to build, especially with straight rails.
Wax, powder and lubrication:
Crokinole boards are heavily laquered and typically finished with a rubbed polyurethane. Several player's wax their boards and discs with carnuba or similar products.
Historically, a carrom or shuffleboard powder was also used during tournament play to try and normalized board speed on a wide variety of player supplied boards. With the standardization of high quality fast boards, many purists would like to see the use of powder reduced or eliminated. It is not uncommon to see a bit of powder in a ditch and high level players rubbing discs in it between shots.
Standardized Boards and Disks:
The 26" in round board has become the standard for most NCA sanctioned tournaments.
Discs have not yet seen the same level of standardization, although it appears to be coming. The preferred disc is slightly convex on 1 side and concave of the other. While seasoned players may be able to feel the difference, newer players can tell by spinning a disc on a flat surface: the concave side down will spin longer.
No Hiding/Promotion: A player must advance at least 1 disc to the 15-circle when the opponent has no discs on the board. Previously, some rules allowed a player to leave a disc behind their posts making the opponents obligation to strike it very difficult.
Damage: Discs moved by a disc that previous was knocked out of play. Modern rules dictate that damage stays. Previously some clubs attempted to restore the board to the previously state.
Spinning Disc: A disc that touches or crosses the shooting line, but does not strike the ditch, rail or out-of-play discs and returns under its own momentum within the shooting line will be considered still in play.