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 September 2013
Can you bow Yoritomo Yukue to pay for Kaimetsu-uo and reduce the gold cost to 0 since him coming into play from your province creates a province? I'm inclined to think no because it's not an action and you don't pay gold for the condition of the effect, but one of our local players wanted me to ask. thanks!
Yoritomo Yukue:
Reaction: Any number of times per turn, put only once per payment, when paying Gold for the cost of an action, or for a condition of an effect, that will gain a player a province, bow Yukue: Reduce the amount needed to be paid to 0 until it is paid.
Kaimetsu-uo:
After the first time this game Kaimetsu-Uo enters play from a province: Gain a province to the left of your leftmost province.
Brook Cunningham (rules official), 25 September 2013
Can you bow Yoritomo Yukue to pay for Kaimetsu-uo and reduce the gold cost to 0 since him coming into play from your province creates a province? I'm inclined to think no because it's not an action and you don't pay gold for the condition of the effect, but one of our local players wanted me to ask. thanks!
Yoritomo Yukue:
Reaction: Any number of times per turn, put only once per payment, when paying Gold for the cost of an action, or for a condition of an effect, that will gain a player a province, bow Yukue: Reduce the amount needed to be paid to 0 until it is paid.
Kaimetsu-uo:
After the first time this game Kaimetsu-Uo enters play from a province: Gain a province to the left of your leftmost province.
You're correct.
Kametsu-uo's cost isn't a direct cost of an action or effect that creates the Province, so he doesn't interact with Yukue.