In 2013 a friend of mine Jason Wotherspoon passed away. Apart from his interest in Aikido, Jason was a huge fan of all things blades and archery. He had a extensive collection and a comprehensive website on shuriken-jutsu called "Secrets of Shuriken-do". Some time before his death he took down the site and this information was lost to us. I managed however to recover much of the site and archive it before it vanished into obscurity. As this material was Jason's and he is no longer able curate it, I am presenting only parts of it and only in pdf format with the links removed, as many no longer work.
If you have time and patience you my be able to recover some of the site including links from https://web.archive.org
In Jason's own words
"Why am I doing this?
Over the years students and visitors to the Takemusu Aiki Association website have been asking about shuriken. Our late headmaster, Morihiro Saito Sensei, taught the art to senior students at Iwama dojo in Japan, and there seemed to be a growing interest in the art worldwide. After finding surprisingly little information on the web, and lots of inaccurate and misleading information, both on the web and in a number of print publications, I decided to make available some form of resource on the web, for shuriken enthusiasts.
These pages are a collection of information on the Shuriken art that I have gathered over the years as part of my research and training. I have gathered information from a variety of reliable sources, such as print media, practitioners of the art, and other researchers. Thanks to the many wonderful people who have emailed me with info about their own experiences with shuriken...one of the more unusual and eclectic traditional arts needing preservation today. Also, some of my own observations and discoveries are added here as well, so this site represents the current state of my knowledge on the subject. Enjoy! - Jason"