"It's harder to play the machine than a human opponent," he said.

First, the game could not be played in "one player" mode; a human opponent was required.

Next month Jack will play in a tournament with human opponents.

She couldn't bring herself to turn it on human opponents again, however.

The player has the option to play against another human opponent.

He might find himself with a human opponent to fight before long.

It wasn't simply a question of a physical battle with human opponents.

One plays against a human opponent; the other helps the user become a better player.

Games can be played against a computer or human opponent.

Best of all, they now give something back to their human opponents by teaching them to become better players.