It's rare to find an editorial which explains the whys and wherefores of a comic book's existence within the title themselves, but 47 Ronin author (and Dark Horse publisher) Mike Richardson offers one in the back matter of 47 Ronin#1. It seems Richardson has spent decades hoping to create a comic book based on the story of the 47 ronin who avenged their dead master, but only recently decided Stan Sakai was the right artist for the project, despite Sakai's long association with Dark Horse.
Unfortunately for fans of Usagi Yojimbo, Sakai has had to take a break from his own series in order to bring this one to life. Fortunately, it does mean fans of Sakai get to see him delving into different (albeit familiar) characters and settings. It's even presented in colour, courtesy of Lovern Kindzierski, while Sakai's work is normally black & white.
47 Ronin recounts a popular tale of Lord Asano, who falls victim to unfortunate politics in 18th century Japan. Asano is devoted to the honour code of bushido, but this is a problem when enemies can manipulate honourable persons by goading them with insults or accusing them of low conduct. I only became familiar with the story after seeing it presented on the Canadian comedy series History Bites, but it's a popular subject in all forms of media, notably the 2005 Image graphic novel Ronin Hood of the 47 Samurai.
Sakai's art is ultimately what drew me to the series (while I patiently wait for Usagi Yojimbo to resume). It's the same level of detail and composition seen in his own work and I'd even assuming he were the author if Richardson's name weren't presented so prominently. Despite knowing how the story resolves, I'm enthused to see how Richardson & Sakai craft it. 47 Ronin will run for only 5 issues total and I encourage you to seek it out.