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.
Both cards change the amount of times the Favor can be used, but do it in different ways. So, what happens when i have a few copies of each in play?
I'm tempted to use the way described in CR: Calculating Stats, but since "times able to use the Imperial Favor" is not a stat, I'm not sure it would be the right call.
If you have X Regal Furisodes and Y Doji Katatas, you get 2 uses of the Limited Favor ability and Y+2 uses of the player Favor Battle ability. 2 because of the Regal Furisodes (it doesn't matter how many, they won't give you more than a second use), plus 1 for each copy of Katata (whose trait provide extra uses of the Favor Battle ability, that "stack", ie add up to those that you currently have)
It would help immensely if you provided links to the previewed cards or quoted the card texts when asking questions about IvE cards. Thanks!