A stage is another measure of how powerful the SP monster is , it is often combined by one of more

A stage

levels/ranks during a SP Summon Operation, it's a Yellow orb placed in top center of the card, with a digit number (from 1 to 12) written on it , SP Monsters gain Sp counters an equal to their current stage after completing summoning procedure stages can't be lower than 1 but they can be above 12 if there's a need to.