Boseiju, Who Shelters All
Legendary Land
Boseiju enters tapped.
, Pay 2 life: Add 
. If that mana is spent on an instant or sorcery spell, that spell can't be countered.
Grey ruins falling into darkness, even with sunlight still shining in the sky.
Jeremy Paillotin
Rulings
The spell can't be countered if the mana produced by Boseiju is spent to cover any cost of the spell, even an additional cost such as a splice cost. This is true even if you pay an additional cost while casting a spell "without paying its mana cost."
(wotc • 2004-12-01)
Suppose mana produced by Boseiju is spent on a spell and an effect creates a copy of that spell. The copy can be countered, even though the original can't.
(wotc • 2004-12-01)
Rulings
The spell can't be countered if the mana produced by Boseiju is spent to cover any cost of the spell, even an additional cost such as a splice cost. This is true even if you pay an additional cost while casting a spell "without paying its mana cost."
(wotc • 2004-12-01)
Suppose mana produced by Boseiju is spent on a spell and an effect creates a copy of that spell. The copy can be countered, even though the original can't.
(wotc • 2004-12-01)