Last Play

In AGA rules White must make the last play. This insures that both players have used the same number of stones.

To quote the AGA rules:

The Last Move: White must make the last move--if necessary, an additional pass, with a stone passed to the opponent as usual. The total number of stones played and passed by the two players during the entire game must be equal.[1]

See also:

• Pass Stone
• Tedomari - Getting the last big move

[1] We don't normally talk about passing stones, but rather about passing moves. Therefore the statement might be better formulated along the lines of the sum of the number of stones played and the number of moves passed by White must be equal to the sum of the number of stones played and the number of moves passed by Black.