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.
A player, 25 November 2008
As far as I read it the only actual changes with determination are because the active player can react first:
1) If the Defender is playing an action, the attacker can react to the announcement of an action before the defender can play determination. (Although there is no situation possible currently that this will make a difference that I can see - since Shinjo Saihan's ability is the only action that can trigger in that time period).
2) On a retribution, the defender is the active player, so he can play reinforce the gates before the attacker has a chance to play determination. This is definitely possible.
Anyway.. I wanted to get the second one out there so people could see it, since it probably won't be obvious for everyone.
Zen Faulkes (rules official), 25 November 2008
As far as I read it the only actual changes with determination are because the active player can react first:
1) If the Defender is playing an action, the attacker can react to the announcement of an action before the defender can play determination. (Although there is no situation possible currently that this will make a difference that I can see - since Shinjo Saihan's ability is the only action that can trigger in that time period).
2) On a retribution, the defender is the active player, so he can play reinforce the gates before the attacker has a chance to play determination. This is definitely possible.
Anyway.. I wanted to get the second one out there so people could see it, since it probably won't be obvious for everyone.
These few little functional changes are why we waited until well after The Race for the Throne and the Samurai Championships were over.
Zen Faulkes (rules official), 25 November 2008
The Rules Junta is examining the interaction of Determination with Reinforce the Gates. We'll let you know if there are any changes.