The US release of Final Fantasy VI was titled "Final Fantasy III".
Canonically this is the sixth Final Fantasy game.
Neither Final Fantasy II or Final Fantasy III were initially released outside Japan, so Final Fantasy IV in North America was released as Final Fantasy II.
Final Fantasy V was also not initially released outside Japan, so Final Fantasy VI in North America was released as Final Fantasy III.
The US Final Fantasy releases were correctly numbered starting with the PSX releases.
User Summary:
A long time ago power beings, called Espers, were created and then unleashed against each other. The resulting battles all but destroyed the world and all of humanity with it. Magic disappeared from the world....
Centuries have since past, and now the world revolves around logic and machinery. Espers are only remembered in myth until one is discovered frozen from ancient times. Magic forces have returned and war is inevitable.
Aside from the engrossing story, the individual characters that you will befriend along your journey to discover the truth behind all the politics are varied and very interesting (to say the least). Battles are turn-based and allow you to attack, use a special ability, use magic (assuming that you've had an Esper teach you the spell), or even call on an Esper to come to your aid.
Final Fantasy VI was Square's third and last Final Fantasy installment for the SNES, and also the last of the core series released for a Nintendo machine.
Individual credits:
Hironobu Sakaguchi: Producer
Nobuo Uematsu: Music
Yoshitaka Amano: Character & monster design
Microbadges: