These moves would be illegal under the optional rule prohibiting suicide.

This is an optional rule to add more realism.

They were gradually phased out in later editions, though the current 4th edition has optional rules for them.

The game comes with several optional rules and the counters necessary to play them out.

Additional optional rules and variants are included in the rulebook.

Back in 1994, companies used their political influence to make the American rule optional, and figured they did not need to worry about the calculations.

Various special and optional rules allow the Players to recreate a picture of an historical event.

This presents both advanced and optional rules which players can selectively use.

Gator, like many childhood games, has hundreds of optional rules.

These describe optional rules and multiply the tactical options allowed.