B-mod is short for balancing modification.

These modifications, developed specifically for individual games, are designed to level the playing field when playing games with children of different ages. Younger children get certain bonuses, which come in a range of different forms, giving them a much greater chance of winning against older children and adults.

This handicap system also enables any adults or older children to play to the best of their ability without the danger of a landslide victory.

Once a child wins a game against another player of a higher level, they level up and will have reduced bonuses the next time they play. In this way, over many plays, they will hope to progress to adult capability. If they ever manage to reach the top level and then defeat an adult without any bonuses, they win a reward which is set when the B-mod is first printed.