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.
Ralph Horsley
Champions of Kamigawa (CHK)
• #273Rulings
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)