Mana Number

Mana Number is a gameplay characteristic of a card (seen at the bottom of the card), displayed by an upside-down number that indicates the amount and civilization of mana that is created when that card is tapped in your mana zone.

Details
The mana number of a card is usually 1 or 0, although there are some exceptions that can alter the mana number to other amounts such as 2 or 3.

Each Light Water Darkness Fire Nature card with each of the 5 civilizations has a mana number of 0, while other cards with 1-3 civilizations have a mana number of 1.

If a card with a mana number of 1 is in your mana zone, you can creature one mana by tapping it.

While the 5-civilization cards provide no amount of mana when tapped, you can add any civilization of mana when you tap them.

After the release of DM-34 Cross Generation, a situational where the mana number of a card can be 2 was started.
 * Heracles, Birther of Gods changes the mana number of Gods in your mana zone from 1 to 2 when they you summon it.
 * The "Original" creature cycle (and one spell) changes the mana number of your Origins from 1 to 2 when you play them.

There are no cards that have an original mana number of 2.

Cards with special types such as Psychic or Dragheart don't have mana numbers because they don't stay in the mana zone.

one if they are moved there) they have no mana value printed on the cards.