506. Triggered Abilities

506.1. Players have a responsibility to remember their own triggered abilities.
506.2. Players are not required to notify other players of triggered abilities they don’t control, but they may if they wish.
506.3. Players must announce their triggers when they occur. If they do not, they are forgotten.
506.4. A triggered ability that was forgotten never goes on the chain.
506.5. A triggered ability that was forgotten is still considered to have triggered for the purpose of non-optional “once a turn” triggers.