A topic from AEG's L5R CCG Rules forum, copied for Oracle of the Void from a copy of the forum saved in October 2015, so pages it didn't save are missing. Players' names are left out; the rules officials are named. Rulings are as they stood on these dates; later rulings, the rulebooks and the Rules Archive may differ.
Can you prevent a terrain from entering play using Ninja tricks? Is "putting the card into play" considered an effect?
Ninja Tricks Reaction: After an action on a Strategy is announced, bow your performing Ninja Personality at the current battlefield: Negate the action's effects. Lose 2 Honor.
All Terrain cards read... Battle: If there are no Terrains in play at the current battlefield: Put this card into play there.
Can you prevent a terrain from entering play using Ninja tricks? Is "putting the card into play" considered an effect?
Yes, and yes.
And after failing to enter play, the Terrain Strategy would be discarded per the normal sequence of playing a Strategy.