Edison format ruling
Blast Magician

Card effect (current official text)Each time a Spell Card is activated, place 1 Spell Counter on this card when that Spell Card resolves. You can remove any number of Spell Counters from this card, then target 1 face-up monster on the field with ATK less than or equal to the number of counters you removed x 700; destroy that target.
Rulings
- If Rush Recklessly is chained to the effect of Blast Magician, and the ATK of the target monster is now higher than 700 x the number of Spell Counters removed, the effect of Blast Magician disappears. You cannot remove additional Spell Counters to increase the effect.
- This is an effect that targets.
- You must remove at least 1 Spell Counter. You cannot activate the effect and remove zero Spell Counters.
- You place a Spell Counter on this card when the Spell Card resolves, so if Magic Jammer is used to negate the Spell Card's activation then you do not place a Spell Counter on this monster. But if Imperial Order is chained to the Spell Card, you still place a Spell Counter on this monster because the activation of the Spell Card was not negated. If the Spell Card was a Continuous, Equip, or Field Spell Card, and "Dust Tornado" is chained to its activation and destroys it before it resolves you still place a Spell Counter because the activation of the card was not negated.
- Blast Magician must have been face-up on the field when the Spell Card was activated (and when it resolves) in order to receive a Spell Counter.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Edison forum — sourced change requests get reviewed.