David A. Tatum wrote:

Subject:
        [FFML] [RK][Fanfic] Guide in the Wilderness, Chapter 1
  Date:
        Fri, 18 Jun 1999 17:33:53 -0400
  From:
        "David A. Tatum" <desaix@sysnet.net>

Description:  Kaoru accidentally kills a man and she
and Kenshin must deal with the legal and philosophical
consequences of her mistake.

Comments:  While clearly written, it wouldn't hurt for
the author to include a couple of sentences of background
on Battosai for those who aren't familiar with the source
material.

Er...
Well, I was writing it primarily for RK fans, and even if you're passingly
familiar with the series, you should know about what\who the Battosai is...
I mean, that's a very large part of what the series is about...

And if it was going to be a really complicated explanation it wouldn't be worth
the effort.  However, I have been introduced to a couple of my favourite series
by fanfiction.  There's no need to leave out the newbies if they can easily be
brought up to speed.