Satsuo Yamamoto's 'Shinobi No Mono' (1962) On R1 USA DVD In Late October 2007.

Exactly the extent to which we will be seeing the eight film series, the first three of which are known for the inclusion of Raizo Ichikawa, it's not known -- the company touted as releasing these films shall, by my lips, remain nameless because they're delving into the realms of not doing a particularly good job, so I would hold off on this and other stuff of theirs until each one plops out a few reviews I can be sure of.

For now, others can talk about this far more eloquently... no official subbed DVD has so far appeared; the HK discs of the films don't seem to have English Subtitles on them. Yes, 'Lone Wolf and Cub' Star Tomisabaru Wakayama is in here somewhere.

Raizo Ichikawa & Shinobi No Mono Series Background Information at SamuraiDVD.
Shinobi No Mono Listing for Conformation, via DVDManiacs.net forum.