Just thought I'd share with you guys, on a whim, I bought a Japanese language
BJJ instructional called Paraestra - Attacks from the Guard. It shows some really cool stuff like 'spiral guard' and 'Sasa sweep'.
The book and combined DVD is authored by Japanese black belt Yuki Sasa.
I reviewed it here:
and Slidey reviews it in more detail here:
I think this stuff is useful if you like to play lots of open guard and the beauty of this book is that you do not need to be able to read Japanese to understand it. I just followed the pictures.