Tanemura Soke recently started a digital book shop with the company DL-MARKET (in Japan). Soke listed up three books already!
A digital book sample link:
NINPO BUGEI Vol.1 FUNDAMENTAL TAIJUTSU
1) The DL-MARKET website has Japanese / English, so you can have your choice of languages.
2) How to reach the Genbukan/KJJR digital book area:
a. Click a "Digital Book" category.
b. Click a "Budo" category.
3) How to purchase:
a. Join DL-MARKET as a member – this is free (no need pay).
b. You can pay with credit cards and soon PayPal also.
* Last detail - Soke will also start "Video Clips" soon!