A Korean website (Ruliweb) has unofficially leaked some information regarding
Final Fantasy III's upcoming port to the Nintendo DS. Supposedly there is a new "Defense Meter" that will be present in battles and play as large a role (if not larger) than a character's HP meter.
Characters attacking foes will result in depleting of the Defense Meter while the enemy is shown trying to block the strike. Once the Defense Meter reaches 0, HP can be taken. Reports have not been clear enough to indicate whether the Defense Meters are exclusive to foes or if the playable characters will have them as well.
There are still no release dates known for the DS port of Final Fantasy IIIj.
Source: RPGamer