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, 30 August 2012
Scenario: I am attacking my opponent with an army consisting of solely Karachu with no attachments, and have no unbowed holdings in play.
My opponent drops Barren Fields into play, and then we both consecutively pass to end the Battle Action Segment. What happens then?
a.) I target and bow Karachu as per the text of the terrain, and then he immediately straightens and stays that way through resolution.
OR
b.) I target and bow Karachu as per the text of the terrain, and he immediately straightens. Since I now have more unbowed cards in my army than unbowed holdings, I have to target and bow a card...etc, etc.
Cards referenced: Barren Fields - http://www.imperialassembly.com/oracle/#cardid=709 Asako Karachu - http://www.imperialassembly.com/oracle/#cardid=551
Brook Cunningham (rules official), 31 August 2012
Scenario: I am attacking my opponent with an army consisting of solely Karachu with no attachments, and have no unbowed holdings in play.
My opponent drops Barren Fields into play, and then we both consecutively pass to end the Battle Action Segment. What happens then?
a.) I target and bow Karachu as per the text of the terrain, and then he immediately straightens and stays that way through resolution.
OR
b.) I target and bow Karachu as per the text of the terrain, and he immediately straightens. Since I now have more unbowed cards in my army than unbowed holdings, I have to target and bow a card...etc, etc.
Cards referenced: Barren Fields - http://www.imperialassembly.com/oracle/#cardid=709 Asako Karachu - http://www.imperialassembly.com/oracle/#cardid=551
In this particular case, Barren Fields' provision of its effect ending when the only cards remaining are those that "cannot bow" should be more loosely interpreted.
So, the effect would end with Karachu straight, since he "cannot [stay] bow[ed]".