# Official draw rules in American checkers

I'm working on a checkers software program and I need to implement the official rules including all possible draws. Following this document, at `1.32.2` it states that the game may end up in a draw, if:

• "Neither player has advanced an uncrowned man towards the king-row during their own previous 40 moves."
• "No pieces have been removed from the board during their own previous 40 moves."

As I understand it, a game can be declared draw after exactly 80 moves or 80 plies of neither player advancing. In my program's code I always reason about the game in terms of plies.

My question is: Did I understand this rule correctly? I have some slight doubts, because I know about the fifty move rule in chess and 50 plies seems reasonably, but 80 feels like too much. And I find the wording in the rules to be a bit weird. So a draw in checkers is considered after 40 plies or 80 plies?

• Just to clarify the situation in chess. The 50-move rule is that a player may claim a draw after 50 moves, that is 100 plies, including the ply in the turn where they claim a draw. Commented May 12 at 7:23
• @rosie I did not know that! Thank you! So the rule means 50 moves for each player, or is one move considered a full turn (2 plies)? If the latter is true, then I find it very confusing. Commented May 12 at 9:30
• 50 moves for each player, thus 100 plies (50 White alternating with 50 Black). In chess we number the moves like this: White's 1st, Black's 1st, White's 2nd, Black's 2nd and so on. Not White's 1st, Black's 2nd, White's 3rd, Black's 4th. Commented May 12 at 9:55
• Indeed the notation of moves, turns and plies is confusing in many situations. Sometimes also tricks, rounds and even games can be confusing. Commented May 12 at 12:05

From Definition of a Draw `1.32.2`: