The End of the Game
The game ends when one player cannot make a legal move, and this can come about in one of two ways. Either when the other player has command of all the pieces, or when his opponent has blocked him in. There are examples of both types of victory in the problems given in this Web site; see Lasca Problems.
The reason for using a 7 x 7 board is to remove corners containing two adjacent white squares; this would allow one player to move an officer repeatedly between the two squares and so prolong the game in a tedious way. As a result it is virtually impossible for the game to end in a draw.
Because no pieces are ever removed from the board, a single rash move when you are almost winning can allow your opponent to attack, liberating a number of his prisoners and thus turning the tables. On the other hand it is reassuring to know that all your men are still on the board, if you can only release them.