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, 28 September 2007
(The sticky about "no Stronger than Steel questions" is still there, but I've seen questions about StS cards answered, so I apologize if I'm still not supposed to ask them)
How do cards which compare Honor Requirement of Personalities (e.g.: A Matter of Honor, "a Personality whose Honor Requirement is 5 points or more lower than your Family Honor") interact with "-" Honor Requirements? is it always impossible to satisfy such conditions with a "-" HR no matter what the Family Honor is, or, if not, how much Family Honor is needed?
A similar, but not necessarily equivalent, question, is what "a lower Honor Requirement" (than another Personality's; cf Failure to your Daimyo) means when one or more of the Personalities has a "-" HR.
Chris Fuchs (rules official), 28 September 2007
http://rules.l5r.com/Card_features#Specific_stats
An Honor Requirement of “-“ on a Personality is treated as an infinitely low value; in other words, a player’s Family Honor can never be lower than the Personality’s Honor requirement. Likewise, whenever an Honor Requirement of “-“ is compared against any other stat, the other stat is always higher. Two Honor Requirements of "-" are considered equal to each other.