field spells.

i was told that only one field card can be active. i thought each player can have one active

This is true. Only one Field Spell card may be face-up on the field at a time. If another Field Spell card is played to the field, the Field Spell that was previously on the field is sent to the Graveyard.

Notice how Naito said "face-up." Another field spell can exist on the field if it remains set on the field.

Confirming what Naito said. In the game there can only be 1 face-up Field Spell on the field at a time, if another Field Spell is activated the one on the field will be destroyed by game mechanics and send to the graveyard. However you can set a field spell if your opponent controls one and activate it at a later time if you choose to.

Also, one thing to point out is that while you have an active field spell on the field, you can still activate a new one, by destroying the one that is already active. However, in this move, there is a brief period in which there is no Field Spell active (right after the original one is destroyed, and before the new one is placed). As a result, any effects that are activated due to a field spell's removal are initiated; for example, Malefic Stardust Dragon would be destroyed during that brief period.

Answered, so locking